CN113677289B

CN113677289B - Removable dental appliance including a bendable tab and an arcuate member

Info

Publication number: CN113677289B
Application number: CN202080028066.5A
Authority: CN
Inventors: 理查德·E·拉比; 埃里克·S·汉森; 迈克尔·K·多姆罗伊塞; 李朝弟
Original assignee: 3M Innovative Properties Co
Current assignee: Shuwanuo Intellectual Property Co
Priority date: 2019-04-11
Filing date: 2020-04-08
Publication date: 2023-08-15
Anticipated expiration: 2040-04-08
Also published as: EP3952785A4; CN113677290B; WO2020208591A1; JP2022528185A; EP3952786A1; JP2022528184A; EP3952786A4; EP3952785A1; US20220211470A1; CN113677290A; CN113677289A; US20220168069A1; WO2020208559A1

Abstract

The present invention relates to a removable dental appliance comprising an appliance body configured to at least partially enclose a plurality of teeth of a patient. The appliance body defines a housing configured to receive a tooth of the plurality of teeth in an initial position; and a flexible flap integrally formed with the appliance body to tether the flap to the housing. The flexible flap defines a border region around the flexible flap and includes a bridge member, wherein the bridge member extends between the body and the flap at or near the border region. In a specific embodiment, the bridge is an arcuate member and comprises a spring bellows. The flexible flap and the bridge are configured to apply a force to the tooth when the removable dental appliance is worn by the patient to cause the tooth to move toward a desired position.

Description

Removable dental appliance including a bendable tab and an arcuate member

Technical Field

The present disclosure relates to polymer-based removable dental appliances such as alignment trays.

Background

The field of orthodontic involves repositioning a patient's teeth to improve function and aesthetic appearance. Orthodontic devices and methods of treatment generally involve applying forces to move teeth into an appropriate bite configuration or bite. As one example, orthodontic treatment involves the use of slotted appliances known as brackets that are secured to the anterior, cuspid and bicuspid teeth of a patient. Archwires are typically placed in the slots of each bracket and act as rails to guide the movement of the teeth to the desired orientation. The ends of the archwire are typically received in an appliance called a buccal tube that is secured to the patient's molars. Such dental appliances remain in the patient's mouth and are regularly adjusted by the orthodontist to check the procedure and maintain the proper force level on the teeth until proper alignment is achieved.

Orthodontic treatment may also involve the use of polymer-based tooth alignment trays such as Clear Tray Appliances (CTAs). For example, orthodontic treatment using CTA includes forming a tray having a shell that couples one or more teeth. Each shell is configured to be in a deformed position from an initial position of the tooth (e.g., a malocclusion position). The deformed position of the respective shell of the CTA applies a force to the respective tooth toward a desired position of the tooth, the desired position being an intermediate position between the initial position and a final position resulting from orthodontic treatment.

Disclosure of Invention

The details of one or more embodiments of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims.

Drawings

FIGS. 1A-1E illustrate a cheek side view, an oblique view, and a mesial cross-sectional view of an exemplary removable dental appliance including a housing and a bendable tab including an arcuate member configured to apply a force to a patient's tooth;

FIGS. 2A and 2B are conceptual diagrams illustrating an exemplary removable dental appliance including a bendable tab having a helical configuration;

3A-3C are conceptual diagrams illustrating an exemplary removable dental appliance including a tab and a pair of spring bellows on opposite ends of the tab;

FIGS. 4A-4C are conceptual diagrams illustrating an exemplary removable dental appliance including a bendable tab and a bridge including a jumper in a plane tangential to a surface of the appliance body;

FIGS. 5A and 5B are conceptual diagrams illustrating an exemplary removable dental appliance including a flexible tab extending from a slotted hinge axis and a plurality of jumpers opposite the hinge axis bridging a tab boundary region in a plane tangential to a surface of the appliance body;

FIGS. 6A and 6B are conceptual diagrams illustrating an exemplary removable dental appliance including a bendable tab extending from a spring bellows extending around an entire tab border area;

FIGS. 7A and 7B are conceptual diagrams illustrating an exemplary removable dental appliance including a bendable tab and a plurality of jumpers bridging the tab boundary area;

FIGS. 8A and 8B are conceptual diagrams illustrating an exemplary removable dental appliance including a flexible tab and a continuous spring bellows extending around the entire tab border area;

FIG. 9 is a block diagram illustrating an exemplary computer environment in which clinics and manufacturing facilities communicate information throughout the dental appliance manufacturing process;

FIG. 10 is a flow chart illustrating an exemplary process of generating digital dental anatomy data;

FIG. 11 is a block diagram illustrating an example of a client computing device connected to a manufacturing facility via a network to generate digital dental anatomy data;

FIG. 12 is a block diagram illustrating an exemplary computer-aided manufacturing system for constructing a removable dental appliance;

FIG. 13 is a flowchart showing a process for constructing a set of removable dental appliances, carried out at a manufacturing facility; and is also provided with

Fig. 14 is a flow chart showing successive iterations of a treatment using an ordered set of removable dental appliances.

Detailed Description

The present disclosure describes a removable dental appliance including at least one tab integrally formed with the appliance body and at least one bridge, which may be an arcuate member, disposed in a respective tab boundary region between the housing and the respective tab. The tab may be formed to extend from the hinge shaft. Orthodontic treatment with removable dental appliances includes the use of at least one tab and at least one bridge in the tab boundary area to allow for better control of the force vector applied to the patient's teeth. When the removable dental appliance is worn by a patient, the tab and bridge apply a force to the tooth to cause the tooth to move toward the desired position. For example, the rest position of the tab may be inwardly convex into the space defined by the desired position of the tooth. The housing may include a surface defining a void inside the housing and shaped to receive a tooth in a desired location. In use of the removable dental appliance, the tab and bridge are displaced by the tooth to a deformed position to generate a force while the surrounding shell remains substantially undeformed. The deformed tab and bridge apply a force to the side of the tooth opposite the void to cause the tooth to move toward the void. In this way, the removable dental appliance including the tab and bridge, and optionally the hinge, may be configured to concentrate deformation in at least one of the tab, hinge axis, or bridge.

By concentrating the deformation in at least one of the tab, hinge axis or bridge, the housing can remain more highly engaged with the tooth. For example, when the removable dental appliance is in a deformed state (e.g., worn by a patient), the housing may have more points of contact with the respective tooth, a greater contact surface area on the respective tooth, etc., than a removable dental appliance without the fins. In this way, the removable dental appliance may improve engagement of the teeth in the shell, concentrate deformation in the tab and bridge, or both. By separating the force generating member (e.g., tab and bridge) and the engaging member (e.g., housing), the removable dental appliance allows for a greater degree of control of the force applied to the patient's teeth. In contrast, for removable dental appliances that do not include at least one tab and bridge or other similar feature, the appliance body both engages the corresponding tooth and generates the force required to move the tooth during orthodontic treatment. The degree of engagement of the teeth (e.g., the number and location of shell/tooth contacts) affects the control of the forces applied to the teeth.

The fins and bridge are configured to control the magnitude, direction, and apparent length of the force applied to the respective tooth. For example, at least one of the position, shape, and size of the fins and/or bridge may produce a desired force vector on the respective tooth. The force vector may be applied to the tooth in a direction and magnitude that would not be possible without the tab and bridge. The fins and bridge also allow the force to be expressed over a greater distance than removable dental appliances that rely on deformation of the appliance's housing to express the force. For example, the resting position of the tab may extend into a space defined by the tooth at the desired location of the tooth such that when the tooth moves into a void shaped to receive the tooth at the desired location, the tab continues to exhibit sufficient force to cause the alveolar bone to remodel. Movement of the teeth causes the bending moment portions of the fins and/or bridge to relax. Some residual stress may remain in the airfoil and/or bridge to ensure a positive force level throughout the performance range. In this way, the removable dental appliance may improve control of at least one of force vector direction, magnitude, or length of performance to achieve at least one of the following compared to other orthodontic treatments: desired tooth movement that may not be achievable without a tab, desired tooth movement within a shortened treatment time, desired tooth movement with less progress of the removable dental appliance in a set of removable dental appliances, and the like.

In some examples, each removable dental appliance in an ordered set of removable dental appliances may result in greater compression than removable dental appliances without fins and bridges (e.g., arc members), for example, because the net shape of the appliance (e.g., the arc shape of at least some of the tray and individual cavities) remains relatively constant during each treatment session. Because the fins and bridge can create a force actuator isolated from the individual teeth, only these focused portions of the appliance (fins and/or bridge) need to deform in order to apply directional forces to the teeth. Thus, all other parts of the appliance can be made fairly rigid, providing a guide channel for tooth movement and support against deformation where movement is not desired. The amount of compression achievable by a single removable dental appliance may be limited by the depth of each tooth receiving void and the elastic limit of possible bending of each bendable tab. For example, the amount of extrusion may be greater than 0.25 millimeters (mm) of crown movement, such as greater than 0.5mm of crown movement or greater than 1mm of crown movement. Greater extrusion and control may reduce the number of removable dental appliances in an ordered set of removable dental appliances required to achieve a selected tooth movement, such as due to more extrusion per removable dental appliance, when coupled with a stabilizing material that retains its aesthetic and mechanical properties over a longer period of time in vivo, as compared to conventional thermoplastics; reduced number of visits, for example due to increased confidence in the progress of the treatment by the physician; reducing treatment duration, e.g., due to more continuous and controlled tooth engagement force and reduced round trip; and enables more accurate trimming, for example due to higher appliance stiffness and positive force application throughout the range of motion.

Fig. 1A-1E illustrate a cheek side view, an oblique cheek side view, and a mesial cross-sectional view of a portion of an exemplary removable dental appliance 100 that includes a plurality of shells 104A-104D (collectively, "shells 104"), the shell 104C including a tab 108C and a bridge 109C configured to apply a force 107C to a tooth 103C of a patient. As shown, the bridge 109C is an arcuate member and will be so identified with reference to fig. 1A-1E. The removable dental appliance 100 includes an appliance body 102 configured to at least partially surround a plurality of teeth 103A-103D (collectively "teeth 103") of a patient's mandibular arch 101. The appliance body 102 includes a housing 104. The housing 104 may be configured to receive the tooth 103. The tab 108C and the arcuate member 109C may be configured to apply a force 107C to the tooth 103C when the removable dental appliance 100 is worn by a patient to cause the tooth 103C to move toward a desired position of the tooth 103C. The desired position may include an intermediate position between the initial position and the final position after orthodontic treatment.

In some examples, the tab 108C and the arcuate member 109C can be configured to apply a force 107C to the attachment on the tooth 103C to cause the tooth 103C to move toward the desired position. The attachment may include natural undercuts, e.g., pointed tips, neck contours, etc., manual undercuts, protrusions, knobs, handles, etc. By applying force 107C to tooth 103C via tab 108C and arcuate member 109C, removable dental appliance 100 may improve control of at least one of force vector direction, magnitude, or manifestation length to achieve at least one of the following compared to other orthodontic treatments: desired tooth movement that may not be achievable without the tab 108C and the arcuate member 109C, desired tooth movement within a shortened treatment time, desired tooth movement with less progress of the removable dental appliance in a set of removable dental appliances, and the like.

For purposes of illustration, only teeth 103, housing 104, and fins 108C are shown in fig. 1A-1E, but appliance body 102 may include any number of housings 104, any number of fins 108, and/or any number of arcuate members 109 configured to at least partially enclose any number of teeth 103. For example, the number of teeth 103 on the dental arch 101 may be fourteen, less than fourteen (e.g., a patient with one or more teeth extracted), or more than fourteen (e.g., a patient with wisdom or multiple teeth). The number of shells 104 may be fourteen, less than fourteen (e.g., at least one shell configured to surround more than one tooth), or more than fourteen (e.g., more than one shell portion configured to surround one tooth). Additionally or alternatively, the appliance body 102 may include a plurality of fins 108 on the same or different housings 104. Additionally or alternatively, one or more of each of the bendable tabs 108 may include one or more arcuate members 109.

The appliance body 102 is configured to at least partially enclose teeth 103 of a maxillary dental arch, or as shown in fig. 1A-1E, a mandibular dental arch 101 of a patient. For example, the appliance body 102 may surround at least one of the buccal, lingual, and occlusal surfaces of the tooth 103, overlap a portion of the gums of the patient, and the like. In some examples, appliance body 102 may enclose different portions of different teeth 103.

The appliance body 102 includes a housing 104. In some examples, appliance body 102 can include a respective housing for housing 104 of each respective tooth 103. In other examples, appliance body 102 may include fewer shells than teeth 103, e.g., a shell may receive more than one tooth, or multiple teeth 103 may not be surrounded by appliance body 102. In other examples, appliance body 102 may include more shells 104 than teeth 103, e.g., two or more shells 104 may enclose at least a portion of at least one tooth 103. Each respective one of the shells 104 can be shaped to receive at least one respective one of the teeth 103. In some examples, the shell 104 can enclose the buccal, lingual, and occlusal portions of the tooth 103. In other examples, the shell 104 may surround fewer portions of the teeth 103, such as only the buccal and lingual portions of the teeth 103, or only one of the buccal and lingual portions. For example, shells 104A, 104B, 104C, and 104D can be shaped to enclose lingual, occlusal, and buccal portions of teeth 103A, 103B, 103C, and 103D, respectively. In some examples, the housing 104 may define a plurality of voids. For example, appliance body 102 may define a frame configured to contact teeth 103 at selected locations. The selected location may include, for example, a portion of an interproximal region between adjacent teeth, an occlusal portion of a tooth, or a portion of a gingival margin of a tooth. The frame may include a material concentrated in regions or along lines as desired to resist deformation caused by internal stresses. These internal stresses result from both forces acting on the appliance body 102, which are typically the result of the flexible tabs 108 elastically deforming as they contact the teeth, and reaction forces, which are typically the result of other portions of the appliance body 102 (e.g., the housing 104) contacting the tooth surface opposite the forces and their respective points of contact. Key benefits of using a frame may include, for example, reduced materials, reduced material costs, reduced manufacturing time, increased aesthetics, and increased saliva flow. Such frames also have the potential to be more rigid than appliances with constant thickness, provided that the increased thickness is used for force line concentration in areas where stress increases in the appliance material. Thus, regions of material experiencing lower or minimal stress are removed. This is basically a process of generating a design, although typically evaluating stress and refining the design after successive iterations is iterative until a diminishing returns (reaching a threshold) is achieved in terms of optimization towards a specific goal, such as maximum stiffness, minimum volume, or a combination thereof. In this manner, the housing 104 can define a plurality of voids to define a frame that contacts at least a portion of at least one of a first interproximal region in a proximal of the respective tooth, a second interproximal region in a distal of the respective tooth, an occlusal surface of the respective tooth, or a gingival margin of the respective tooth.

In some examples, the respective housings may not include fins (e.g., housings 104A, 104B, and 104D). In some examples, the respective shell may apply a force to the respective received tooth by deformation of the respective shell. For example, the housings 104A, 104B, and 104D may deform when worn by a patient. This deformation may create a restoring force when the respective housing is moved towards the undeformed configuration. The restoring force may be transferred to the respective tooth via one or more contact points between the respective shell and the respective tooth. In this way, the removable dental appliance 100 may incorporate some of the shells 104 including the fins with some of the shells 104 deformed to move the teeth 103 to the desired positions of the teeth 103. In other examples, the respective housing may be configured to be sufficiently rigid so as not to deform. The non-deforming corresponding housing may provide anchoring for an adjacent housing (e.g., a housing including the fins 108). The selection of which shells 104 include the fins 108 may depend on the force exerted on the respective teeth 103, the movement of the respective teeth 103, or both. For example, the respective shell 104 may not include the tab 108 when deformation of the respective shell 104 does not interfere with the force to be applied to the adjacent tooth 103 or the movement of the adjacent tooth 103. Conversely, when the deformation of the respective shell 104 does interfere with the force to be applied to the adjacent tooth 103 or the movement of the adjacent tooth 103, the respective shell 104 may include a tab 108 to reduce the deformation of the respective shell 104.

In some examples, appliance body 102 may include one or more anchor housings configured to receive one or more anchor teeth. In some examples, the anchor teeth may include one or more molars, premolars, or both. In other examples, the anchor teeth may include one or more anterior teeth, or a combination of one or more anterior and posterior teeth. The anchor housing may be configured to allow the appliance body 102 to deform to generate a force sufficient to move the selected tooth (e.g., a force sufficient to cause remodeling of the alveolar bone) without generating a force sufficient to move the corresponding anchored tooth.

The shell 104C can be shaped to engage the tooth 103C in an initial position of the tooth 103C. To engage the initial position of tooth 103C, the inner surface of shell 104C may contact at least one selected location, selected surface area, or both of tooth 103C. For example, as shown in fig. 1C, the surface 111C of the shell 104C may contact at least a portion of the occlusal and lingual surfaces of the tooth 103C in the initial position. The location of contact, the surface area of contact, or both, may affect the force 107C applied by the flexible flap 108C to the tooth 103C, the resulting movement of the tooth 103C, or both.

The shell 104C can also be shaped to receive the tooth 103C in a desired position of the tooth 103C. The desired position of tooth 103C can be a position after force 107C has been applied to tooth 103C to move tooth 103C to the extent possible in housing 104C. For example, the surface 111C may define a void 119C inside the housing 104C. As shown in fig. 1C, the void 119C comprises a wedge-shaped void having a maximum depth near the gingival edge of the tooth 103C that gradually decreases to a minimum near the axis of rotation 116C at the incisal edge of the tooth 103C. The wedge shape of void 119C may conform to the path of tooth 103C as tooth 103C moves toward the desired position defined by surface 111C. Tooth 103C can be moved through gap 119C toward the desired position until tooth 103C contacts surface 111C. In this way, surface 111C may prevent tooth 103C from moving beyond a desired position.

Removable dental appliance 100 includes at least one tab 108C. In general, any number of fins may be positioned on any number of housings 104. The tab 108C may be integrally formed with the housing 104C of the appliance body 102 to extend from the hinge 110C such that the tab 108C is a bendable tab because the tab 108C may be bent around the hinge in the housing 104C. Hereinafter, a flap tethered to a housing at one or more bridges, hinge points, sections or axes may be described as a bendable flap. Hinge 110C extends in a mesial-distal direction along a cutting edge of housing 104C. In general, the respective bendable tabs 108 may extend in any direction from the respective hinge axis 110 extending along any portion of the respective housing. By selecting the length and orientation of the respective hinge axis 110, the removable dental appliance 100 may be configured to apply a corresponding stress to any portion of the respective tooth via the respective flexible tab 108.

As shown in fig. 1A-1E, the flexible tab 108C extends from the hinge axis 110C on the buccal surface of the appliance body 102 and is positioned on the buccal side of the removable dental appliance 100. The appliance body 102 defines a tab border region 113C that extends around the flexible tab 108C from the first end 114C to the second end 112C. The tab border region 113C may include regions of reduced shear and tensile stress as compared to the surrounding portion of the appliance body 102. For example, at least a portion of the airfoil boundary region 113C includes a bridge, here an arcuate member 109C.

The bridge 109C may increase the flexibility of the device body 102 at the tab border region 113C as compared to the surrounding device body 102. As shown in fig. 1A-1E, the bridge 109C may include a spring bellows (e.g., a strip of material) that extends around at least a portion of the flap boundary region 113C and is coupled to the housing 104C and the bendable flap 108C. In some examples, bridge 109C may include a plurality of spring bellows. In other examples, the bridge 109C may include one or more jumpers (e.g., a bar of material) that define an arc in a plane tangential to the surface of the housing 104C or extend out of a plane tangential to the surface of the housing 104C and are coupled to the housing 104C and the bendable tab 108C. Spring bellows and jumpers are exemplary arcuate members. In some examples, bridge 109C may include any suitable combination of one or more spring bellows, one or more jumpers, or one or more shear force reduction regions. The bridge 109C, along with the hinge 110C, serves as at least one connection between the flap 108C and the housing 104C. In other embodiments, explored in more detail below, one or more bridges are used as the sole structure to tether the tab to the housing.

The bridge 109C may have an arcuate, sinusoidal, saw tooth, pulse wave, spiral, helical, or folded cross-section in a plane tangential to the surface of the housing 104C and/or a plane perpendicular to the surface of the housing 104C. The position (e.g., relative to the housing 104C and the pliable tab 108C) and shape of the bridge 109C may be selected to allow cantilever movement of the pliable tab 108C and to apply a selected force 107C to the tooth 103C via the pliable tab 108C when the removable dental appliance 100 is worn by a patient.

In some examples, the bridge 109C may be made of the same material as the housing 104C. For example, the bridge 109C may be integrally formed with the housing 104C. In some examples, the bridge 109C may be formed by laser cutting portions of the tool body 102 to define the bridge member 109C. Additionally or alternatively, the bridge 109C may be formed by reshaping (e.g., heating and applying force) a portion of the appliance body 102 or coupling additional material to a surface of the appliance body 102 (e.g., by adhesion, thermal welding, ultrasonic welding, etc.). In some examples, at least a portion of the bridge 109C may be thinner than the housing 104C to allow for greater flexibility, such as a spring bellows or jumper. In some examples, at least a portion of the bridge 109C may be thicker than the housing 104C to allow for greater stiffness or toughness of the spring bellows or jumper. In some examples, the bridge 109C may include a different material or additional material, such as a material having a higher modulus relative to the material of the appliance body 102, a metal (wire, strip, or sheet), or the like. The material and fabrication of bridge 109C may be selected to allow cantilever movement of flexible flap 108C and application of a selected force 107C to tooth 103C via flexible flap 108C when removable dental appliance 100 is worn by a patient.

In examples where bridge 109C includes one or more spring bellows, the spring bellows may include a continuous or discontinuous curvilinear portion of appliance body 102, such as an arc, half wave, full wave shape, saw tooth, sinusoidal, pulse wave, or spiral. In some examples, the arcuate displacement may include at least one fold to increase the length and/or flexibility of the spring bellows. The length of the spring bellows may be selected to provide a selected force resulting from deformation of the spring bellows when the removable dental appliance 100 is worn by a patient.

In examples where the spring bellows includes a continuous curve, the arcuate displacement may define an outer radius of curvature, e.g., an outermost surface of the spring bellows. In some examples, the outer radius of curvature may be between about 0.5 millimeters and about 3 millimeters, or between about 0.75 millimeters and about 1.5 millimeters, or about 1.0 millimeters. The radius of curvature may be substantially constant or may vary along an interproximal boundary curve. The spring bellows may also define a displacement distance extending between a centerline of the tab border region 113C and a centerline of the spring bellows. In some examples, the displacement distance may be less than about 3 millimeters, or less than about 1 millimeter, or less than about 0.75 millimeters, or about 0.5 millimeters. The displacement distance may be substantially constant or may vary along the airfoil boundary region 113C.

The thickness of the spring bellows may be less than the thickness of the housing 104C and the bendable tabs 108C such that the spring bellows deforms more than the housing 104C and the bendable tabs 108C to concentrate compression, tension, shear, bending, or torsion in the spring bellows. The thickness of the spring bellows may be between about 0.025 millimeters and about 1.0 millimeters, or between about 0.1 millimeters and about 0.75 millimeters, or between about 0.15 and about 0.6 millimeters, or about 0.3 millimeters. The thickness of the spring bellows may be substantially constant or vary along the tab border region 113C.

In some examples, the spring bellows may define at least one shear force reduction region, e.g., at least one void or cut in the spring bellows. The at least one shear force reduction region may concentrate deformation of the spring bellows in selected portions of the spring bellows. The terminal positions of the spring bellows on the housing 104C and the flexible flap 108C may be selected to provide a selected force direction and magnitude when the removable dental appliance 100 is worn by a patient. In some examples, the bridge 109C may include a plurality of spring bellows, each respective one of which is disposed along a respective portion of the airfoil border region.

By selecting the shape, length, radius of curvature, and displacement distance of the spring bellows, the removable dental appliance 100 can control at least one of the direction, magnitude, and apparent length of the force on the flexible flap 108 caused by the deformation of the appliance body 102 when the removable dental appliance 100 is worn by a patient. Other spring bellows constructions are described in International publication WO/2019/069162 (Raby et al), which is incorporated herein by reference in its entirety.

In examples where bridge 109C includes jumpers, these jumpers include elongated structures that extend along a longitudinal axis between a first end coupled to any suitable portion of housing 104C or a different housing 104 (e.g., not directly adjacent to bendable tab 108C) and a second end coupled to any suitable portion of bendable tab 108C. At least a portion of the force 107C is caused by deformation of the jumper wire when the removable dental appliance 100 is worn by a patient. For example, when the removable dental appliance 100 is worn by a patient, the patch cord may be deformed to apply at least one of a bending, twisting, compression, tension, or shear force on the first and second ends such that selection of the position of the first and second ends may control the direction and magnitude of the force 107C.

The jumpers can include any suitable shape along the longitudinal axis of the elongated structure, such as, for example, at least one of an arc, fold, zigzag, sinusoidal, spiral, helical, or spiral shape extending between a first end of the jumpers and a second end of the jumpers. In some examples, the elongate structure may include at least one fold. In some examples, a middle portion of the jumper (e.g., between the first end and the second end) may extend away from a plane tangential to a surface of the housing 104C. In other examples, the middle portion of the jumper may be substantially in a plane tangential to the surface of the housing 104C (e.g., less than about 0.5mm from the plane).

In some examples, the patch cord may include an arcuate shape with an outer radius of curvature (e.g., an outermost surface of the patch cord) of between about 0.5 millimeters and about 5 millimeters. In some examples, the jumper may include a displacement distance (e.g., a distance between a plane tangent to a surface of the housing 104C and a midline of an inner radius of the jumper) of less than about 2 millimeters, or less than about 1 millimeter, or less than about 0.5 millimeters, or about 0.5 millimeters. The jumper may define a cross-section in a plane perpendicular to the longitudinal axis of the elongated structure having any suitable shape, area, or aspect ratio selected to provide a selected force to the flexible tab 108C. The cross-section may be constant in shape, area, or aspect ratio, or vary along the longitudinal axis.

The jumpers can include any suitable thickness selected to control the magnitude and direction or concentrated location of the force 107C generated by the deformation of the appliance body 102 when the removable dental appliance 100 is worn by a patient. In some examples, the patch cord may be more flexible than the housing to at least one of reduce deformation of the housing or concentrate stresses in the patch cord when the removable dental appliance is worn by the patient. In some examples, the thickness of the appliance body 102 is increased near at least one of the first end or the second end of the jumper wire, for example, to improve toughness at the intersection of the first end and the second end with the appliance body 102. The thickness of the patch cord may be substantially constant or may vary in a tapered or stepped manner along the elongated structure. In some examples, the thickness of the jumper may be between about 0.1 millimeters and about 3.0 millimeters, or between about 0.3 millimeters and about 1.0 millimeters.

In some examples, the appliance body may include a gingival portion coupled to the second end of the jumper wire (the first end coupled to the bendable tab 108C) to at least partially anchor the appliance body 102 to the alveolar process via the gums. In some examples, the bridge 109C may include a plurality of jumpers, each respective one of which includes a respective elongated structure extending between a respective first end coupled to a respective location on the housing and a respective second end coupled to a respective location on the bendable tab.

By selecting the shape, length, radius of curvature, and displacement distance of the patch cord, the removable dental appliance 100 can control at least one of the direction, magnitude, and apparent length of the force on the flexible flap 108 caused by the deformation of the appliance body 102 when the removable dental appliance 100 is worn by a patient. Other jumper configurations are described in International publication WO/2019/069164 (Raby et al), which is incorporated herein by reference in its entirety.

In some examples, bridge 109C may cause at least a portion of force 107C, bendable tab 108C may remain relatively unbent in the deformed portion, or both. When removable dental appliance 100 is worn by a patient or fitted to a tooth, bridge 109C may achieve at least one of the following: such that the surface contact of flexible flap 108C with tooth 103C increases; reducing accumulation of food particles or plaque in the tab border area 113C or other portions of the appliance body 102; and reducing interference between the flexible flap 108C and the patient's dental anatomy.

In some examples, the housing 104C may be thinner or include one or more voids along the hinge axis 110C. Thinner material or voids along hinge 110C may relieve bending stresses in bendable tab 108C. For example, at least a portion of the flap boundary region 113C may also define one or more cuts or slits in the appliance body 102. Removing material from the airfoil boundary region 113C effectively eliminates both shear and tensile stresses in the airfoil boundary region 113C. Additionally or alternatively, at least a portion of the tab border region 113C may include an elastomeric polymer or material having a lower modulus of elasticity than the appliance body 102, a region of reduced thickness of the appliance body 102, or the like, to increase the flexibility of the tab border region 113C as compared to the surrounding appliance body 102. In this way, tab border region 113C may allow flexible tab 108C to deflect in the lingual direction, reduce the amount of deformation in flexible tab 108C to increase the contact area between flexible tab 108C and tooth 103C, or both to improve control of tooth movement. In examples where the flap boundary region 113C includes an elastomeric material, the elastomeric material may be selected to allow the flexible flap 108C to deflect in the buccal-lingual direction, covering at least a portion of the flap boundary region 113C to reduce accumulation of food particles or plaque in the flap boundary region 113C or other portion of the appliance body 102 or both.

The flexible flap 108C, bridge 109C, and optional hinge 110C may be configured to apply a force 107C to the buccal surface of the tooth 103C. For example, the resting position of the flexible flap 108C may protrude inwardly into the space defined by the tooth 103C at the desired location of the tooth 103C such that when the removable dental appliance 100 is worn by a patient, the initial position of the tooth 103C may cause deformation of the flexible flap 108C and the bridge 109C. Deformation of the flexible flap 108C and the bridge 109C may generate a force 107C, such as a restoring force, as the flexible flap 108C and the bridge 109C move toward an undeformed configuration. The rest positions of the flexible tab 108C and bridge 109C may be selected to reduce interference with the cutting edge of the tooth 103C when the removable dental appliance 100 is assembled onto the tooth. Additionally or alternatively, the pliable tab 108C may include an angled surface near the gingival portion of the pliable tab 108C such that when the removable dental appliance 100 is fitted onto a tooth, the angled surface deflects or otherwise reduces interference with the cutting edge of the tooth 103C with the pliable tab 108C and bridge 109C.

In response to force 107C, tooth 103C can move through void 119C toward the desired position until tooth 103C contacts surface 111C. In some examples, if only a portion of tooth 103C contacts surface 111C, while leaving a gap elsewhere, a force couple may be formed between the contact point and force 107C. The resulting couple may cause tooth 103C to move, e.g., "walk," to a position that is more aligned with surface 111C. For example, tooth 103C may move in alternating stages of translation and rotation until tooth 103C is received in a position substantially coincident with surface 111C. In some examples, surface 111C can be positioned outside of a desired position of tooth 103C to compensate for recurrence of tooth 103C back toward an intermediate or initial position of tooth 103C. In this way, the shape of the shell 104C and the inner surface may be selected to enable control of the location of the force and resulting movement of the tooth 103C. Similar effects are also possible for the housings 104A, 104B, and 104D.

Force 107C can be transferred from tab 108C and bridge 109C to tooth 103C through one or more points of contact of tab 108C with tooth 103C. For example, the interior surface of the tab 108C can contact at least a portion of the tooth 103C. In some examples, the interior surface of the flap 108C can be shaped to conform to the shape of the tooth 103C at the desired location of the tooth 103C such that contact between the flexible flap 108C and the tooth 103C increases as the tooth 103C moves toward the desired location. In some examples, the thickness of the tab 108C may be selected to control the number or location of contact points. In some examples, the tab 108C may be divided (e.g., by laser cutting) into a plurality of tabs that control the number or location of contact points. In other examples, the tab 108C may include at least one protrusion on an interior surface of the flexible tab 108C. The protrusion may be positioned or shaped to transfer the force 107C to at least one selected portion of the tooth 103C. For example, the tab 108C may include at least one protrusion near the gingival portion of the tab 108C such that force transmission of the force 107C to the tooth 103C is concentrated near the gingival edge. By focusing the force transmission near the gingival margin, the tab 108C may more effectively induce a twist or root tilt of the tooth 103C. In this manner, the protrusions on the respective fins may be used to control the transmission of the respective forces to achieve or enhance the effectiveness of tooth movement (e.g., translation, rotation, tilting, twisting, convex, concave, or a combination).

In some examples, as shown in fig. 1C, when removable dental appliance 100 is worn by a patient, rotational axis 116C may be substantially fixed or anchored to other portions of the dental anatomy, such as teeth 103A, 103B, and 103D, by appliance body 102. The application of force 107C to the portion of tooth 103C near the gingival edge via tab 108C and bridge 109C may form a force couple with rotational axis 116C. The coupling may comprise two opposing forces at a distance. For example, when the force 107C moves the tooth 103C in such a way that the center of resistance is located near the center of the root of the tooth 103C, the fixed rotational axis 116C of the housing 104C may apply a second opposing force to the incisal edge of the tooth 103C. By forming a couple with the rotational axis 116C, the force 107C may cause a rotation 118C of the tooth 103C toward the void 119C, e.g., a root tilt or torsional movement. In this way, the contact location, contact surface area, or both, of the surface 111C of the housing 104C can affect the force 107C applied to the tooth 103C, the resulting movement of the tooth 103C, or both.

When the removable dental appliance 100 is fitted to or removed from the tooth 103, the tab 108C and bridge 109C may deflect in the lingual-buccal direction as the tab 108C and bridge 109C deform to accommodate the tooth 103C. Deflection may cause stress near the first end 114C and the second end 112C of the hinge 110C and/or in the case where the bridge 109C is coupled to the housing 104C and the tab 108C. To reduce stress caused by deflection of the fins 108C and/or the bridge 109C, the appliance body 102 may define a stress concentration reduction region. The diameter of the circular stress concentration reduction region may be at least greater than the width of the airfoil boundary region 113C. As the fins 108C and bridge 109C deflect, the stresses may be distributed around the circular stress concentration reducing region to reduce localized concentrations of stresses that might otherwise tear or cause wear of the appliance body 102. Reducing localized stress concentrations may reduce wear on the appliance body 102 and increase the useful life of the removable dental appliance 100.

By allowing the tab 108C to deflect in the lingual direction, the tab 108C and bridge 109C may be configured to apply a force 107C to a side of the tooth 103C opposite the void 119C to cause the tooth 103C to move toward the void 119C. For example, the tab 108C may be configured to project inwardly into the space defined by the desired position of the tooth 103C when the tab 108C is in the rest position. In some examples, the desired position of the tooth 103C is a position after the tooth 103C contacts at least a portion of the surface of the appliance body 102 defining the cavity 119C inside the housing 104C. As shown in fig. 1E, tab 108C projects inwardly into the space defined by tooth 103C. By protruding inwardly into the space defined by tooth 103C in the desired position, tab 108C and bridge 109C can apply force 107C to tooth 103C by tooth 103C moving into void 119C. For example, as shown in fig. 1C, when tooth 103C is in the initial position, tab 108C and bridge 109C may apply force 107C to tooth 103C. As seen in fig. 1D, when tooth 103C is in the desired position, tab 108C and bridge 109C apply force 107C to tooth 103C. When the tooth 103C is in the desired position, the force 107C may be greater than the minimum force that causes the alveolar bone to remodel. In this manner, removable dental appliance 100 may enable full extrusion of tooth 103C through void 119C to a position substantially coincident with surface 111.

In some examples, the appliance body 102 may include gingival regions 106A, 106B, 106C, and 106D (collectively, "gingival regions 106") that overlap at least a portion of a patient's gums (e.g., gingival edges). For example, the gingival area may extend around a gingival portion of the housing 104 where the teeth 103 meet the gums. The gingival region 106 may be configured to use at least a portion of the gingiva, the alveolar process, or both for anchoring. For example, when worn by a patient, the gingival region 106 may at least partially contact the gums to obtain additional support provided by the gingival region 106 that indirectly engages the alveolar process without interfering with the mobility of the teeth 103. Additionally or alternatively, by increasing the extent of the housing 104 with the gingival region 106, more force may be applied to selected teeth of the teeth 103 while using more rigid alveolar processes rather than adjacent teeth as anchors. In this way, the gingival region 106 may allow for better control of tooth movement (alveolar process) relative to a fixed reference without causing undesirable reactive movement of adjacent teeth. In some examples, the appliance body 102 may exclude the gingival region 106.

In some examples, the appliance body 102 may comprise a single material, such as a single uniform material. A single material may comprise a single polymer or a homogeneous mixture of one or more polymers. For example, removable dental appliance 100 may be composed of a single, continuous 3D printed or thermoformed component. In other examples, the appliance body 102 may include multiple layers of material. The multi-layer material may enable one or more portions of the appliance body 102 to be formed from multiple layers having different moduli of elasticity to enable selection of force characteristics, displacement characteristics, or both of the flexible flap 108C. The multi-layer material may comprise multiple layers of a single material, such as a single polymer, or multiple layers of multiple materials, such as two or more polymers, and another material. For example, removable dental appliance 100 may be composed of multiple layers of 3D printed or thermoformed components. Suitable polymers may include, but are not limited to: a (meth) acrylate compound; an epoxy resin; an organosilicon; a polyester; polyurethane; a polycarbonate; mercapto-vinyl polymers; acrylate polymers such as urethane (meth) acrylate polymers, polyalkylene oxide di (meth) acrylates, alkane diol di (meth) acrylates, aliphatic (meth) acrylates, silicone (meth) acrylates; polyethylene terephthalate-based polymers such as polyethylene terephthalate (PETG); polypropylene; ethylene vinyl acetate; etc. The thickness of the appliance body 102 may be in a range between about 0.10 millimeters and about 2.0 millimeters, such as between about 0.2 millimeters and about 1.0 millimeters, or between about 0.3 millimeters and about 0.75 millimeters. In the same or different examples, removable dental appliance 100 may include chamfers or fillets on the edges and other spaces of removable dental appliance 102. Such chamfers or fillets may improve patient comfort and reduce visibility of the removable dental appliance 100. In the same or a different example, the removable dental appliance 100 may include at least one stiffening structure to increase the stiffness of the area of the appliance body 102 (e.g., the bendable tab 108C or the arcuate member 109C) to increase the strength of the area of the appliance body 102 (e.g., the hinge axis 110C).

In some examples, removable dental appliance 100 may include a metal component configured to enhance the force applied by removable dental appliance 100 to one or more of the enclosed teeth. For example, the metal component may include a metal wire, such as bendable tab 108C or arc-shaped member 109C, having any suitable cross-sectional shape (e.g., circular, rectilinear, or strip) that extends through at least a portion of the appliance body 102. In some examples, removable dental appliance 100 may include one or more other metal components, such as a metal bite component, where greater durability is required to overcome the stress of high pressure bite contacts (such as caused by biting or chewing). In some examples, removable dental appliance 100 may include a clasp for connecting to an anchoring device (e.g., a temporary anchoring device or a miniscrew) implanted in a patient. For example, the clasp may be positioned on the anchor housing to connect to an anchor on the anchor tooth. In this way, such removable dental appliance 100 may provide a hybrid construction of metal and plastic. While the plastic component may be substantially transparent so as to reduce visibility, the metal component may include a plating or other coloring layer to reduce visibility of the removable dental appliance 100 when worn by a patient. For example, the metal component positioned near the patient's teeth 103 when worn may include a white coating or plating such as rhodium, silver, white anodized titanium, teflon, PTFE, or the like, or be formed of a white metal such as rhodium, silver, white anodized titanium, or the like. The metal parts that are positioned elsewhere may be colored to substantially match the tissue color in the patient's mouth.

In some examples, the respective fin or fins may define a helical configuration. Fig. 2A-2B are conceptual diagrams illustrating an exemplary removable dental appliance 200 including a tab 208 having a helical configuration. Except for the differences described herein, removable dental appliance 200 may be the same as or substantially similar to removable dental appliance 100 discussed with reference to fig. 1A-1E.

The helical configuration of the tab 208 may enable the tab (or tabs) to apply a force near the center of the helix and distribute corresponding deformations around the circumference of the helix. In these and other embodiments, not shown, any number of fins may be arranged in a helical configuration to increase the effective length of the resulting cantilever. For example, as shown in fig. 2A, the appliance body 202 may include two wings 208A that define a single wing boundary region 213A defining a double helix configuration. When in the rest position, the center 215A of the tab 208A may protrude inward into the space defined by the desired position of the tooth. In the deformed position, the tab 208A can deform to concentrate the deforming force on the tooth near the center 215A when worn by the patient. The deforming force of the tab 208A may be transferred to the appliance body 202 around the periphery 210 of the helical configuration. In some examples, as shown in fig. 2B, the helical configuration may include a four-helical configuration with a plurality of bendable tabs 208C, 208D, 208E, 208F. In some examples, removable dental appliance 200 may include a bridge as discussed above with reference to fig. 1A-1E.

In some examples, the respective flap may lack a hinged connection with the appliance body and may be tethered by one or more bridges. Fig. 3A-3C are conceptual diagrams illustrating an exemplary removable dental appliance 300 that includes a tab 308 coupled to a body 302 by a pair of spring bellows 309, 310 (i.e., bridge). Except for the differences described herein, removable dental appliance 300 may be the same as or substantially similar to removable dental appliance 100 discussed with reference to fig. 1A-1E.

As shown in fig. 3A-3C, the tab 308 is movable relative to the appliance body 302 in a direction toward the tooth surface (see, e.g., fig. 3C). Thus, the tab 308 is a bendable tab. The flexible tab 308 defines a slotted side 313. Slotted side 313 may include a hole extending through appliance body 302. In other examples, slotted side 313 may include any suitable type of region of reduced shear resistance as compared to an adjacent portion of appliance body 302. The appliance body 302 includes a pair of bridges 309, 310 presented on opposite ends of the flap 308. As shown in fig. 3B, the bridges 309, 310 may define displacement of the appliance body 302 away from a plane tangential to the surface of the flexible flap 308. As shown in the cross-sectional views of fig. 3B and 3C, the thickness 314 of at least one of the bridges 309, 310 may be substantially less than the thickness of the other portions of the appliance body 302 (including the tab 308 and the housing) (not shown). In some examples, the bridges 309, 310 may each act as a spring and store potential energy. By combining the bending moments of the flexible tabs 308 and/or the bridges 309, 310, the total bending moment may be very close to the bending moment near horizontal, approximately 10N greater than what either of the flexible tabs 308 and/or the bridges 309, 310 could achieve independently. In some examples, the flexible tabs 308 and/or the bridges 309, 310 may be simpler and easier to engineer and manufacture than, for example, a continuous spring bellows surrounding a U-shaped flexible tab. For example, forces in the flexible tabs 308 and/or the bridges 309, 310 are easier to model and calculate than, for example, a continuous spring bellows surrounding a U-shaped flexible tab. Such simplified modeling may reduce computational effort or time when determining the position, size, and shape of the fins and arcuate members to provide selected forces to the teeth to achieve a selected treatment plan. Additionally or alternatively, the bendable tabs 308 and/or the bridges 309, 310 may be easier to machine, as only a linear cutting path may be required. In some examples, the flexible tabs 308 and/or bridges 309, 310 may be mass produced as prefabricated components and later attached to the forming tool body 302. In such examples, the flexible tabs 308 and/or bridges 309, 310 may be formed using a continuous linear extrusion of material and cutting the flexible tabs 308 and/or bridges 309, 310 into individual components of any given width. In some examples, at least a portion of the appliance body 302 adjacent to the flexible tab 308 may define a void (e.g., the slot 313 may be enlarged). In some examples, by not transmitting forces directly to appliance body 302 adjacent to flexible flap 308, deformation of appliance body 308 may be reduced when such concerns are recognized, or in examples where close proximity of adjacent structures may cause the fit of appliance body 302 to teeth to be compromised due to such deformation.

In some examples, the appliance body may include a tab tethered to the appliance body 402 by a pair of bridges 409, 410 that include zigzag springs in a plane tangential to the surface of the appliance body. Fig. 4A-4C are conceptual diagrams illustrating an exemplary removable dental appliance 400 that includes a tab 408 and bridges 409, 410 in planes tangential to the surface of the appliance body 402. Similar to tab 108, tab 408 is a bendable tab. Except for the differences described herein, removable dental appliance 400 may be the same as or substantially similar to removable dental appliance 100 discussed with reference to fig. 1A-1E.

As shown in fig. 4A-4C, the flexible flap 408 is tethered by bridges 409, 410 on opposite sides of the flap 408 body. The flexible flap 408 also defines a slotted side 413. The slotted side 413 may include a hole extending through the appliance body 402. In other examples, slotted side 413 may include any suitable type of region of reduced shear resistance as compared to an adjacent portion of appliance body 402. The bridge 409, 410 comprises a zigzag spring 412 in a plane tangential to the surface of the appliance body 402. In some examples, the arcuate bridges 409, 410 may enable the bendable flap 408 to move in a direction perpendicular to a plane tangential to the surface 411 of the flap as well as in a lingual-labial direction (see, e.g., fig. 4C). In some examples, movement of the flexible flap 408 may improve compression during movement of the corresponding tooth. In some examples, the configuration shown in fig. 4A-4C may effectively isolate the housing 404 from the reaction forces. In some examples, the flexible tabs 408 and/or bridges 409, 410 may be easier to machine because an end mill or laser cutter may be used to cut features into the tool body 402 after thermoforming the tool body 402. Thus, the configurations shown in fig. 4A-4C may be applicable to design constraints and manufacturing methods for appliances requiring a substantially constant thickness. In some examples, by removing material along the zigzag spring, the deformation of the flexible flap 408 may be reduced to increase the contact area with the teeth or allow for more predictable points of contact. In some examples, the configuration shown in fig. 4A-4C may be more comfortable for the patient by less protruding in the direction of the tongue, lips, or cheeks. Many variations of the bridges 409, 410 are possible, such as, for example, one or more jumpers or variations of the amplitude, width, length, attachment points, etc. of the one or more jumpers.

In some examples, the appliance body may include a flap and a plurality of bridges extending over a flap boundary region. Fig. 5A and 5B are conceptual diagrams illustrating an exemplary removable dental appliance 500 including a tab 508 extending from a slotted hinge axis 510 and a plurality of jumpers 509 opposite the hinge axis 510 bridging a tab boundary region 513 in a plane tangential to a surface of the appliance body 502. Similar to wings 308 and 408, wing 508 is a bendable wing. Except for the differences described herein, removable dental appliance 500 may be the same as or substantially similar to removable dental appliance 100 discussed with reference to fig. 1A-1E.

As shown in fig. 5A and 5B, the flexible flap 508 extends from the appliance body 502 at a slotted hinge 510. The flexible flap 508 defines a flap boundary region 513. The appliance body 502 includes a plurality of bridges 509 extending from the housing 504 to the flexible tabs 508. Although six bridges 509 are shown, in other examples, the appliance body 503 may include fewer or more bridges 509. The bridge 509 comprises a plurality of zigzag springs in a plane tangential to the surface of the appliance body 502. In some examples, bridge 509 may enable flexible flap 508 to move in a plane tangential to the surface of appliance body 502 and in a lingual-labial direction. In some examples, movement of the flexible flap 508 may improve compression during movement of the corresponding tooth. Additionally or alternatively, the plurality of bridges 509 may improve control of the direction or magnitude of force applied to the tooth surface by the flexible flap 508. The configuration shown in fig. 5A and 5B may achieve increased force compared to other configurations by placing additional bridges 509 along the sides of the bendable flaps 508. In some examples, the bridge 509 may be omitted from the distal end of the flexible flap 508 (e.g., the end furthest from the hinge axis) to allow the flexible flap 508 to be positioned closer to an adjacent tooth structure or force actuator. In some examples, the configuration shown in fig. 5A and 5B may allow for a more flexible bendable tab 508 by reducing the number of bridges 509 and increasing the length of one or more of the bridges 509. This may be accomplished by an increased available length when utilizing the tab border region 513 on the lateral side of the flexible tab 508 in addition to the distal end region of the flexible tab 508.

In some examples, the appliance body may include a fin and an arcuate member defining a spring bellows bridging at least a portion of a fin border region. Fig. 6A and 6B are conceptual diagrams illustrating an exemplary removable dental appliance 600 that includes a tab 608 and a spring bellows 609 extending around the entire tab border region 613. Like the tabs 108, 208, 308, 408, and 508, the tab 608 is a bendable tab. Except for the differences described herein, removable dental appliance 600 may be the same as or substantially similar to removable dental appliance 100 discussed with reference to fig. 1A-1E.

As shown in fig. 6A and 6B, the appliance body 602 includes a bridge 609 extending around the entire flap boundary region 613. As shown in fig. 6A and 6B, the bridge 609 may define displacement of the appliance body 602 away from a plane tangential to the surface of the flexible flap 608. As shown in the cross-sectional view of fig. 6B, the bridge 609 may have a thickness that is substantially less than the thickness 612 of the rest of the appliance body 602 (including the flexible flap 608 and/or the housing). The relatively thin bridge 609 may be more flexible than the surrounding instrument body 602 or the bendable tabs 608. Additionally or alternatively, in some examples, one or more portions of the bridge 609 may include slots to reduce shear stress in selected areas. As shown in fig. 6B, bridge 609 may comprise a continuous spring bellows. The continuous spring bellows may further protrude from the plane surrounding the tab border region 613. In some examples, bridge 609 may include a plurality of undulations toward and away from a plane tangential to the surface of appliance body 602. Such undulations may improve control over the direction and/or magnitude of force applied to the bendable vane 608 by the bridge 609. The configuration shown in fig. 6A and 6B may increase patient comfort by eliminating exposed edges of the appliance material, provide significantly more force than other examples by increasing the effective length of the spring bellows to include lateral sides of the fins, and/or reduce accumulation of food and plaque, as compared to an appliance body having voids defining arcuate members. In some examples, the appliance body 602 may include rounded corners or chamfers to improve patient comfort and/or reduce accumulation of food or plaque in corners or inside edges of the appliance body 602. In some examples, the appliance body 602 may be thermoformed without post-processing, such as machining or cutting. In some examples, depending on the orientation of the appliance in the printer (because the exposed edges that may lack local support are eliminated), the appliance body 602 may be 3D printable without the need for support structures on or near the flexible flap 608.

In some examples, the appliance body may include a flap and a plurality of bridges defining jumpers bridging at least a portion of the flap boundary region. Fig. 7A and 7B are conceptual diagrams illustrating an exemplary removable dental appliance 700 that includes a flexible tab 708 and a plurality of jumpers 709 bridging the tab boundary region 713. Except for the differences described herein, removable dental appliance 700 may be the same as or substantially similar to removable dental appliance 100 discussed with reference to fig. 1A-1E.

As shown in fig. 7A and 7B, the appliance body 702 includes jumpers 709 bridging the flap boundary region 713 to tether the flap 708 to the body 702. As shown in fig. 7A and 7B, jumper 709 may define the displacement of appliance body 702 away from a plane tangential to tab 708. Although four jumpers 709 are shown, in other examples, the appliance body 702 may include fewer or more jumpers 709. The thickness of the jumper 709 may be substantially less than the thickness of other portions of the appliance body 702, including the flexible tab 708 and the housing (not shown). The relatively thin jumper 709 may be more flexible than the surrounding instrument body 702 or the bendable tab 708. Additionally or alternatively, in some examples, one or more portions of the jumper 709 may include slots to reduce shear stress in selected areas. In some examples, the force may be reduced by interrupting the continuity of the jumper 709 with discrete through holes or shear reduced areas, thereby reducing the overall area of the jumper 709 without reducing the thickness to the point of compromising durability, formability, printability, etc. The jumpers 709 can also be placed only on the lateral sides of the flexible tabs 708 to reduce the aspect ratio or overall length of the flexible tabs 708. In some examples, the void defined by appliance body 702 (e.g., jumper 709) may increase saliva flow around the tooth and through the appliance, which may facilitate flushing out acids that may cause enamel demineralization, caries white spots, caries, gingivitis, etc. if in contact with the tooth for prolonged periods of time. The flexible tab 708 may also include an open area 719 at the center of the tab, such that the tab 708 resembles a ring or circle as shown in fig. 7B.

In some examples, the appliance body may include a fin and an arcuate member defining a spring bellows bridging at least a portion of a fin border region. Fig. 8A and 8B are conceptual diagrams illustrating an exemplary removable dental appliance 800 that includes a tab 808 and a spring bellows 809 that extends around the entire tab border area 813. Similar to tabs 208, 308, 408, 508, 608, and 708, tab 808 is a bendable tab. Except for the differences described herein, removable dental appliance 800 may be the same as or substantially similar to removable dental appliance 100 discussed with reference to fig. 1A-1E.

As shown in fig. 8A and 8B, the appliance body 802 includes a bridge 809 that extends around the entire flap boundary region 813. As shown in fig. 8A and 8B, bridge 809 may define the displacement of appliance body 802 away from a plane tangential to the surface of housing 804. As shown in the cross-sectional view of fig. 8B, the bridge 809 may have a thickness that is substantially less than the thickness 812 of other portions of the appliance body 802, including the flexible tabs 808 and/or the housing. The relatively thin bridge 809 may be more flexible than the surrounding instrument body 802 or bendable tab 808. Additionally or alternatively, in some examples, one or more portions of bridge 809 may include slots to reduce shear stress in selected areas. As shown in fig. 8B, bridge 809 may comprise a continuous spring bellows. The continuous spring bellows may further protrude from the plane surrounding the tab border area 813. In some examples, bridge 809 may include a plurality of undulations toward and away from a plane tangential to the surface of appliance body 802. Such undulations can improve control over the direction and/or magnitude of force applied to the pliable airfoil 808 by the bridge 809.

The flexible tab 808 includes a reduced surface area as compared to the tab 608 such that it can be used to concentrate forces on a smaller area or point on a given tooth surface, thereby providing a relatively well-defined point of contact for the applied force. In some cases, a relatively smaller tab may be advantageous to provide a controllable engagement force position, direction, magnitude, or combination thereof, resulting in greater tooth movement and control (e.g., translation and/or rotation). These considerations indicate that the flexible tab 808 (as well as other tabs of reduced surface area) may be particularly advantageous for completing movement during the end phase of treatment or during phases in which tooth movement may be accomplished by a couple of forces (e.g., rotation).

The configuration shown in fig. 8A and 8B may increase patient comfort by eliminating exposed edges of the appliance material, provide significantly more force than other examples by increasing the effective length of the spring bellows to include lateral sides of the fins, and/or reduce accumulation of food and plaque, as compared to an appliance body having voids defining arcuate members. In some examples, the appliance body 802 may include rounded corners or chamfers to improve patient comfort and/or reduce accumulation of food or plaque in corners or inside edges of the appliance body 802. In some examples, the appliance body 802 may be thermoformed without post-processing, such as machining or cutting. In some examples, depending on the orientation of the appliance in the printer (because the exposed edge that may lack local support is eliminated), the appliance body 802 may be 3D printable without the need for support structures on or near the flexible tabs 808.

In general, the respective tab and bridge may be integrally formed with the respective housing on any one of the lingual, buccal or occlusal sides of the respective appliance body. The flexible tabs and bridges may be arranged to achieve linear translation, rotation, intrusion, extrusion, tilting and torsion. In some examples, the plurality of flexible tabs and the plurality of bridges may be located on opposite sides of the appliance body. Two or more flexible tabs in such examples may be positioned to form a couple. The couple of forces may cause the tooth to rotate about an axis approximately centered in the tooth and extending in the occlusal-gingival direction. As another example, one flexible tab may be configured to apply a force to the lingual-proximal middle surface of the tooth opposite the void to cause the tooth to move toward the void inside the appliance housing and be shaped to receive the tooth in a desired position. In some other examples, the plurality of flexible tabs may be located on the same side of the appliance body. In such examples, one flexible flap and/or bridge may be configured to apply a force to a surface near the incisal edge of the tooth, and the individual flexible flap bridge combination applies a force to a surface near the gingival edge. These forces may be concentrated at different locations on the tooth in similar or dissimilar magnitudes as desired. In some other examples, a plurality of flexible tabs and bridges on the same side of the appliance body may be configured to concentrate a corresponding plurality of forces. Suitable arrangements for the flexible tabs and bridges of the present disclosure can be found in, for example, U.S. provisional patent application 62/832524 to Raby et al, filed on date 2019, 4, 11, which is assigned to the present assignee and is incorporated herein by reference in its entirety.

Fig. 9 is a block diagram illustrating an exemplary computer environment 10 in which a clinic 14 and manufacturing facility 20 communicate information throughout the manufacturing process of a set of removable dental appliances 22 of a patient 12. A set of removable dental appliances 22 may include at least one of removable dental appliances 100, 200, 300, 400, 500, 600, 700, or 800. As described above, the removable dental appliance 100, 200, 300, 400, 500, 600, 700, or 800 includes a plurality of shells, at least one bendable tab, and at least one bridge and/or hinge. First, the orthodontist of the clinic 14 generates one or more images of the dental anatomy of the patient 12 using any suitable imaging technique, and generates digital dental anatomy data 16 (e.g., a digital representation of the dental structure of the patient 12). For example, a physician may generate an X-ray image that may be digitally scanned. Alternatively, the physician may capture digital images of the patient's dental structure using, for example, conventional Computed Tomography (CT), laser scanning, intraoral scanning, dental impression CT scanning, scanning of dental casts cast by impressions, ultrasound instruments, magnetic Resonance Imaging (MRI), or any other suitable three-dimensional (3D) data acquisition method. In other embodiments, the digital image may be provided using a handheld intraoral scanner developed by, for example, blonetwikipedia technology company (Brontes Technologies, inc. (Lexington, massachusetts)) in Lexington, leschachusetts, massachusetts) using active wavefront sampling and described in PCT publication WO 2007/084727 (Boerjes et al), which is incorporated herein by reference in its entirety. Alternatively, other intraoral scanners or intraoral contact probes may be used. As another option, the digital dental anatomy data 16 may be provided by scanning a negative impression of the teeth of the patient 12. As yet another option, the digital dental anatomy data 16 may be provided by imaging a male physical model of the teeth of the patient 12 or by using a contact probe on a model of the teeth of the patient 12. The model for scanning may be made, for example, by: by casting an impression of the dentition of the patient 12 from a suitable impression material, such as alginate or polyvinyl siloxane (PVS), a casting material, such as orthodontic plaster or epoxy, is poured into the impression and allowed to cure. The model may be scanned using any suitable scanning technique, including those described above. Other possible scanning methods are described in U.S. patent application publication 2007/0031791 (Cinader et al), which is incorporated herein by reference in its entirety.

In addition to providing a digital image by scanning the exposed surface of the tooth, invisible features of the dentition, such as the root of the patient's 12 teeth and the jawbone of the patient 12, may be imaged. In some embodiments, digital dental anatomy data 16 is formed by providing several 3D images of these features and then "stitching" them together. These different images need not be provided using the same imaging technique. For example, a digital image of a tooth root with a CT scan may be integrated with a digital image of a tooth crown with an intraoral visible light scanner, e.g., as described in U.S. patent application 62/787,025 to Raby et al, which is incorporated herein by reference in its entirety. Scaling and registration of two-dimensional (2D) dental images with 3D dental images is described in us patent 6,845,175 (Kopelman et al), which is incorporated herein by reference in its entirety, as well as in us patent publication 2004/0029068 (Badura et al), which is incorporated herein by reference in its entirety. Issued U.S. patent 7,027,642 (Imgrund et al), which is incorporated herein by reference in its entirety, and issued U.S. patent 7,234,937 (Sachdeva et al), which is incorporated herein by reference in its entirety, describe techniques for integrating digital images provided by various 3D sources. Thus, as used herein, the term "imaging" is not limited to ordinary photographic imaging of visually distinct structures, but also includes imaging of dental anatomy that is hidden from view. The dental anatomy may include, but is not limited to, any portion of the crown or root of one or more teeth of the dental arch, gums, periodontal ligament, alveolar bone, cortical bone, implant, artificial crown, bridge, veneering, denture, orthodontic appliance, or any structure that may be considered as part of the dentition before, during, or after treatment.

In order to generate digital dental anatomy data 16, the computer must convert the raw data from the imaging system into a usable digital model. For example, for raw data representing tooth shapes received by a computer, the raw data is typically slightly more than a point cloud in 3D space. Typically, the point cloud is planar to create a 3D object model of the patient's dentition, including one or more teeth, gingival tissue, and other surrounding oral structures. To make this data available for orthodontic diagnosis and treatment, the computer may "segment" the dentition surface to produce one or more discrete, movable 3D dental object models representing individual teeth. The computer may also separate these tooth models from the gums into separate objects.

Segmentation allows a user to characterize and manipulate the tooth arrangement in the form of a set of individual objects. Advantageously, the computer may derive diagnostic information such as arch length, bite position, gap spacing between adjacent teeth, and even the american orthodontic committee (ABO) objective score from these models. Another benefit is that digital orthodontic settings may provide flexibility in the manufacturing process. By replacing the physical process with a digital process, the data acquisition step and the data manipulation step can be performed at separate locations without the need to transport the plaster model or impression from one location to another. Reducing or eliminating the need for reciprocal transport of physical objects can result in significant cost savings for both the customer and manufacturer of the custom appliance.

After generating the digital dental anatomy data 16, the clinic 14 may store the digital dental anatomy data 16 within the patient record in the database. The clinic 14 may, for example, update a local database having a plurality of patient records. Alternatively, the clinic 14 may update the central database remotely via the network 24 (optionally within the manufacturing facility 20). After storing the digital dental anatomy data 16, the clinic 14 electronically transmits the digital dental anatomy data 16 to the manufacturing facility 20. Alternatively, manufacturing facility 20 may retrieve digital dental anatomy data 16 from a central database. Alternatively, manufacturing facility 20 may retrieve pre-existing digital dental anatomy data 16 from a data source that is not associated with clinic 14.

The clinic 14 may also forward prescription data 18 to the manufacturing facility 20, which conveys general information regarding the physician's diagnosis and treatment plan for the patient 12. In some examples, prescription data 18 may be more specific. For example, the digital dental anatomy data 16 may be a digital representation of the dental anatomy of the patient 12. The physician of the clinic 14 can view the digital representation and indicate at least one of a desired movement, spacing, or final position of the individual teeth of the patient 12. For example, the desired movement, spacing, and final position of the individual teeth of the patient 12 may affect the force applied to the teeth of the patient 12 by each removable dental appliance in the set of removable dental appliances 22 at each stage of treatment. As described above, by selecting the size, shape, and location of at least one of the plurality of shells (e.g., shells 104, 204, 304, 404, 504, 604, 704, or 804), at least one flexible tab (e.g., flexible tab 108C, 208, 308, 408, 508, 608, 708, or 808), at least one bridge (e.g., arcuate member 109C, 209, 309, 409, 509, 609, 709, or 809), etc., the force applied by each removable dental appliance (e.g., removable dental appliance 100, 200, 300, 400, 500, 600, 700, or 800) of the set of removable dental appliances 22 may be determined. At least one of a desired movement, spacing, or final position of the individual teeth of the patient 12 may enable a physician, a technician manufacturing the apparatus 20, and a computer manufacturing the apparatus 20 to determine at least one of a selected size, shape, and position of at least one of the shell, the flexible flaps, the arcuate members, and the reinforcement structure. In this manner, the digital dental anatomy data 16 may include at least one of a size, shape, and position selected by a practitioner, technician, or computer of at least one of a shell, a flexible flap, a bridge, and an optional reinforcement structure of each of the removable dental appliances in the set of removable dental appliances 22 to result in a desired movement of the teeth of the patient 12. After viewing the digital representation, the digital dental anatomy data 16 including the selected size, shape, and location of the shell, flexible tab, arcuate member, and stiffening structure of each removable dental appliance in the set of removable dental appliances 22 may be forwarded to the manufacturing facility 20. Manufacturing facility 20 may be located off-site or with clinic 14.

For example, each clinic 14 may include field devices for manufacturing facility 20 so that treatment planning and digital design may be performed entirely by a clinician or assistant in a clinical setting using locally installed software. Manufacturing may also be performed in the clinic using a 3D printer (or by other additive manufacturing methods). The 3D printer allows for the manufacture of complex features of the dental appliance or physical representations of the dental anatomy of the patient 12 by additive printing. The 3D printer may use the original dental anatomy of the patient 12 and the iterative digital design of the desired dental anatomy of the patient 12 to fabricate a plurality of digital appliances, a digital appliance pattern customized to fabricate the desired dental anatomy of the patient 12, or both. Manufacturing may include post-processing to remove uncured resin and to remove support structures, or to assemble various components, which post-processing may also be necessary and may also be performed in a clinical setting.

The manufacturing facility 20 utilizes the digital dental anatomy data 16 of the patient 12 to construct the set of removable dental appliances 22 to reposition the teeth of the patient 12. After a period of time since, manufacturing facility 20 forwards the set of removable dental appliances 22 to clinic 14, or alternatively, directly to patient 12. For example, the set of removable dental appliances 22 may be an ordered set of removable dental appliances. The patient 12 then wears the removable dental appliances 22 of the set of removable dental appliances 22 sequentially over time according to the prescription schedule to reposition the teeth of the patient 12. For example, patient 12 may wear each removable dental appliance of the set of removable dental appliances 22 for a period of between about 1 week and about 6 weeks, such as between about 2 weeks and about 4 weeks, or about 3 weeks. Optionally, the patient 12 may return to the clinic 14 to periodically monitor the progress of treatment using the removable dental appliance 22.

During such periodic monitoring, the clinician may adjust the prescription schedule of patient 12 for sequentially wearing the removable dental appliances of the set of removable dental appliances 22 over time. Monitoring typically includes visual inspection of the teeth of the patient 12 and may also include imaging to generate digital dental anatomy data. In some examples, the clinician may decide to discontinue treatment of patient 12 with the set of removable dental appliances 22, for example, by: the newly generated digital dental anatomy data 16 is sent to a manufacturing facility 20 for making a new set of removable dental appliances 22. In some examples, the clinician may send the newly generated digital dental anatomy data 16 to the manufacturing facility 20 after completing the prescription schedule of the treatment with the removable dental appliance 22. In some examples, after completing the prescription schedule of treatment with removable dental appliance 22, the clinician may request a new set of removable dental appliances from manufacturing facility 20 to continue treatment of patient 12.

Fig. 10 is a flow chart illustrating a process 30 performed at the clinic 14 according to one example of the present disclosure. First, a physician at the clinic 14 collects patient identity and other information from the patient 12 and creates a patient record (32). As described above, patient records may be located within the clinic 14 and optionally configured to share data with databases within the manufacturing facility 20. Alternatively or additionally, the patient records may be located within a database at the manufacturing facility 20 that is remotely accessible to the clinic 14 via the network 24 or within a database that is remotely accessible to both the manufacturing facility 20 and the clinic 14.

Next, digital dental anatomy data 16 for patient 12 may be generated using any suitable technique (34) to create a virtual dental anatomy. The digital dental anatomical data 16 may be composed of a two-dimensional (2D) image, a three-dimensional (3D) representation, or both, of the dental anatomy.

In one example, a Cone Beam Computed Tomography (CBCT) scanner such as an i-CAT 3D dental imaging device (available from international imaging technologies (Imaging Sciences International, LLC; 1910N Penn Road,Hatfield,PA)) 1910N Penn Road,Hatfield,Pennsylvania of hatfeldebrand bine northwest 1910, pa) is used to generate a 3D representation of a dental anatomy. The clinic 14 stores 3D digital dental anatomy data 16 (in the form of radiological images) generated by CBCT scanners in a database located within the clinic 14 or alternatively within the manufacturing facility 20. The computer system processes digital dental anatomy data 16 from the CBCT scanner, which may be in the form of a plurality of slices, to calculate a digital representation of the tooth structure that may be manipulated within the 3D modeling environment.

If a 2D radiological image is used (36), the physician may also generate 3D digital data (38). The 3D digital dental anatomy data 16 may be generated, for example, by: a physical impression or mold of the dental structure of the patient 12 is formed and then digitally scanned. For example, a physical impression or mold of the dental arch of patient 12 may be scanned using a visible light scanner, such as an OM-3R scanner (available from Laser Design, inc., minneapolis, minnesota) or an ato scanner (available from GOM company of brinz, germany (GOM GmbH, braunschweig, germany)). Alternatively, the practitioner may generate the 3D digital dental anatomy data 16 of the occlusion mechanism by using an intraoral scan of the dental arch of the patient 12 or using existing 3D tooth data. In one example, a method of forming a digital scan through a mold or stamp as described in U.S. patent 8,491,306 to Raby et al, which is incorporated herein by reference in its entirety, may be used. In the same or a different example, techniques for defining virtual tooth surfaces and virtual tooth coordinate systems described in U.S. patent application publication 2013/0325231 to See et al, which is incorporated herein by reference in its entirety, may be used. In any event, the digital data is digitally registered within the 3D modeling environment to form an integrated digital representation of a tooth structure, which may include the root of the tooth and the occlusal surface.

In one example, prior to generating both the radiological image and the 3D digital scan, the 2D radiological image and the 3D digital data of the occlusal surface of the dental arch are registered to the dental structure of the patient 12 with a first incidental registration mark (e.g., a fiducial mark or a base having a known geometry). The registration techniques described in us patent 8,491,306 may then be used to align the 2D radiological image and the data representation of the registration markers within the 3D digital data within the 3D modeling environment.

In another example, 3D digital data of the tooth structure is generated by combining two 3D digital representations of the tooth structure. For example, the first 3D digital representation may be a relatively lower resolution image of the tooth root obtained from a CBCT scanner (e.g., an i-CAT 3D dental imaging device), and the second 3D digital representation may be a relatively higher resolution image of the tooth crown obtained by an industrial CT scan of an impression of the patient's dental arch or by a visible light (e.g., laser) scan of a casting mold of the patient's dental arch. The 3D digital representations may be registered using a software program such as geomic Studio software (3D systems, inc. 333 Three D Systems Circle,Rock Hill,South Carolina, 3D systems loop 333 available from mountain, south carolina) that enables manipulation of the 3D representations within a computer environment, or alternatively, registration techniques described in us patent 8,491,306 may be used.

Next, a computer system executing 3D modeling software renders a resulting digital representation of a tooth structure including occlusal surfaces and a root structure of a patient's dental arch. Modeling software provides a user interface that allows a physician to manipulate a digital representation of teeth in 3D space relative to a digital representation of a patient's dental arch. By interacting with the computer system, the physician generates treatment information (40), for example, by selecting an indication of the desired position, final position, or both, of the individual teeth of the patient 12, the duration of the corresponding treatment phase or number of treatment phases, the direction or magnitude of the forces on the teeth of the patient 12 during the treatment phase, and the like. In some examples, the flexible flap may be used during at least one but less than all phases of the treatment. For example, the desired position of an individual tooth of the patient 12, the duration of the corresponding treatment phase, or the number of treatment phases may affect the direction or magnitude of the force applied by each removable dental appliance of the set of removable dental appliances 22 to the tooth of the patient 12 at each treatment phase. As described above, by selecting the size, shape, and location of at least one of the plurality of shells (e.g., shells 104, 204, 304, 404, 504, 604, 704, or 804), the flexible tab (e.g., flexible tab 108C, 208, 308, 408, 508, 608, 708, or 808), the at least one bridge (e.g., bridge 109C, 209, 309, 310, 409, 509, 609, 709, or 809), the optional stiffening structure, etc., the force exerted by each removable dental appliance (e.g., removable dental appliance 100, 200, 300, 400, 500, 600, 700, or 800) of the set of removable dental appliances 22 may be determined. In this manner, updating the database with diagnostic and treatment information (40) may include automatically determining or selecting, by a physician, technician, or by a computer, the size, shape, and location of each of the removable dental appliances of the set of removable dental appliances 22, the at least one flexible tab, the at least one reinforcing structure, etc., to result in a desired movement of the teeth of the patient 12.

Once the physician has completed communicating general information related to diagnosis and treatment plans within the 3D environment, the computer system updates the database associated with the patient records to record prescription data 18 (42) that conveys general information related to diagnosis and treatment plans specified by the physician. The prescription data 18 is then forwarded to the manufacturing facility 20 for the manufacturing facility 20 to construct one or more removable dental appliances, such as removable dental appliance 22, including at least one flexible tab (44).

Although described with respect to an orthodontist located at an orthodontist office, one or more of the steps discussed with respect to fig. 10 may be performed by a remote user (such as a user located at manufacturing facility 20). For example, an orthodontist may send only radiographic image data and impressions or casts of the patient to the manufacturing facility 20 where the user interacts with the computer system to formulate a treatment plan within the 3D modeling environment. Optionally, the digital representation of the treatment plan within the 3D modeling environment may then be transmitted to an orthodontist of the clinic 14, who may view the treatment plan and either return its approval or indicate the desired modification.

Fig. 11 is a block diagram illustrating an example of a client computer 50 connected to manufacturing facility 20 via network 24. In the illustrated example, a client computer 50 provides an operating environment for modeling software 52. Modeling software 52 presents a modeling environment for modeling and rendering a 3D representation of the teeth of patient 12. In the example shown, modeling software 52 includes a user interface 54, an alignment module 56, and a rendering engine 58.

The user interface 54 provides a Graphical User Interface (GUI) that visually displays a 3D representation of the teeth of the patient 12. In addition, the user interface 54 also provides an interface for receiving input from the physician 60 of the clinic 14, e.g., via a keyboard and pointing device, touch screen, etc., to manipulate the teeth of the patient 12 within the modeling dental arch.

Modeling software 52 is accessible to manufacturing facility 20 via network interface 70. Modeling software 52 interacts with database 62 to access various data, such as treatment data 64, 3D data 66 related to the dental structure of patient 12, and patient data 68. Database 62 may be represented in various forms including a data storage file, a lookup table, or a database management system (DBMS) executing on one or more database servers. The database management system may be a Relational (RDBMS), hierarchical (HDBMS), multidimensional (MDBMS), object oriented (ODBMS or OODBMS), or Object Relational (ORDBMS) database management system. For example, the data may be stored within a single relational database such as SQL server from Microsoft corporation (Microsoft Corporation). Although database 62 is shown as being local to client computer 50, the database may also be remote from client computer 50 and coupled to client computer 50 via a public or private network (e.g., network 24).

The treatment data 64 describes diagnostic or repositioning information for the teeth of the patient 12 selected and positioned by the physician 60 within the 3D modeling environment. For example, the treatment data 64 may include the size, shape, and location of at least one of the plurality of shells (e.g., shells 104, 204, 304, 404, 504, 604, 704, or 804), the flexible flap (e.g., flexible flap 108C, 208, 308, 408, 508, 608, 708, or 808), at least one bridge (e.g., bridge 109C, 209, 309, 310, 409, 509, 609, 709, or 809), an optional stiffening structure, etc., which may result in the selected magnitude and direction of the force vector being applied to the patient's teeth (e.g., tooth 103) throughout the treatment plan.

Patient data 68 describes a group of one or more patients (e.g., patient 12) associated with physician 60. For example, patient data 68 specifies general information for each patient 12, such as name, date of birth, and dental treatment history.

The rendering engine 58 accesses and renders the 3D data 66 to generate a 3D view that is presented to the physician 60 through the user interface 54. More specifically, the 3D data 66 includes information defining a 3D object representing each tooth (optionally including the root) and jaw bone within the 3D environment. Rendering engine 58 processes each object to render a 3D triangle based on the perspective of physician 60 within the 3D environment. The user interface 54 displays the rendered 3D triangle to the physician 60 and allows the physician 60 to change the perspective and manipulate objects within the 3D environment.

U.S. patent 8,194,067 to Raby et al, which is incorporated by reference in its entirety, and U.S. patent 7,731,495 to Eisenberg, which is incorporated by reference in its entirety, describe other examples of computer systems and 3D modeling software with user interfaces that can be used with the techniques described herein.

The client computer 50 includes a processor 72 and memory 74 to store and execute modeling software 52. Memory 74 may represent any volatile or non-volatile storage element. Examples include Random Access Memory (RAM) such as Synchronous Dynamic Random Access Memory (SDRAM), read-only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), and FLASH (FLASH) memory. Examples may also include non-volatile storage devices such as hard disks, magnetic tape, magnetic or optical data storage media, compact Discs (CDs), digital Versatile Discs (DVDs), blu-ray discs, and holographic data storage media.

Processor 72 represents one or more processors, such as a general purpose microprocessor, a specially designed processor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a set of discrete logic, or any type of processing device capable of performing the techniques described herein. In one example, memory 74 may store program instructions (e.g., software instructions) that are executed by processor 72 to implement the techniques described herein. In other examples, these techniques may be performed by specially programmed circuitry of processor 72. In these or other ways, the processor 72 may be configured to perform the techniques described herein.

Client computer 50 is configured to send a digital representation of the 3D dental structure of the patient, and optionally treatment data 64 and/or patient data 68, to computer 80 of manufacturing facility 20 via network 24. The computer 80 includes a user interface 82. The user interface 82 provides a GUI that visually displays a 3D representation of a digital model of a tooth. In addition, the user interface 82 provides an interface for receiving input from a user, for example via a keyboard and pointing device, to manipulate the patient's teeth within the digital representation of the patient's 3D dental structure.

Computer 80 may be further configured to automatically determine the size and shape of each removable dental appliance in a set of removable dental appliances 22. The size and shape of the removable dental appliance 22 may include the position, size and shape (e.g., at least one of the at least one position, the at least one size and the at least one shape) of at least one of the plurality of shells, the at least one bendable tab, the at least one arcuate member, the at least one stiffening structure, etc., such that the removable dental appliance 22 is configured to reposition one or more teeth from their initial position to their final position when the removable dental appliance is worn by a patient. As described above with respect to fig. 1-17, the location, size, and shape of at least one of the plurality of shells (e.g., shells 104, 204, 304, 404, 504, 604, 704, or 804), the flexible flap (e.g., flexible flap 108C, 208, 308, 408, 508, 608, 708, or 808), the at least one bridge (e.g., bridge 109C, 209, 309, 310, 409, 509, 609, 709, or 809), the optional stiffening structure, etc., may affect the magnitude, direction, and length of the force applied to the teeth when the removable dental appliance is worn by the patient. For example, when the removable dental appliance is worn by a patient, the position, size, and shape of the respective bendable tabs and/or the arc-shaped members may at least partially determine the magnitude, direction, and length of expression of the force generated by the deformation of the bendable tabs and/or the arc-shaped members. The location, size, and shape of the arcuate members and/or optional reinforcing structures may concentrate deformation in selected areas of the respective flexible tabs to control the direction of force applied to the teeth. Moreover, the position, size, and shape of a respective shell of the plurality of shells can affect the position of engagement of the respective shell with the respective tooth. One or more engagement locations can affect the direction of force applied to the respective tooth. The computer 80 may analyze at least one of a magnitude, a direction, and a performance length of at least one force generated by deformation of the respective bendable tabs and/or the arc-shaped members when the removable dental appliance is worn by the patient to determine at least one of a position, a size, and a shape of the respective housing, the respective bendable tabs, the respective arc-shaped members, the respective stiffening structures, etc. that will result in a desired movement of the respective teeth of the patient when the removable dental appliance is worn by the patient.

Computer 80 may present a representation of removable dental appliance 22 for viewing by a user, including viewing size and shape. Alternatively or additionally, the computer 80 may accept input from a user to determine the size and shape of the set of removable dental appliances 22 for the patient 12. For example, the user input may affect at least one of an automatically determined size or shape. The computer 80 may transmit or otherwise send the digital model of the set of removable dental appliances 22, the size and shape of the set of removable dental appliances 22, or both to a computer-aided manufacturing system 84 for producing the set of removable dental appliances 22.

Client computer 50 and computer 80 are conceptual representations of only exemplary computer systems. In some examples, the functionality described with respect to client computer 50, computer 80, or both, may be combined into a single computing device or distributed among multiple computing devices within a computer system. For example, cloud computing may be used for digital design of dental appliances described herein. In one example, a digital representation of the tooth structure is received at a computer at a clinic, while a different computer, such as computer 80, is used to determine the shape and size of the removable dental appliance. Furthermore, the different computer (such as computer 80) may not have to receive all of the same data in order for it to determine shape and size. The shape and size may be determined without receiving a complete 3D representation of the considered case based at least in part on knowledge derived from an analysis of the historical case or a virtual model of the exemplary case. In such examples, the data transmitted between client computer 50 and computer 80 or otherwise used to design the custom dental appliance may be significantly less than a complete data set representing a complete digital dental model of the patient.

Fig. 12 is a block diagram illustrating an exemplary computer-aided manufacturing system 1500 for constructing a removable dental appliance 1522. Examples of computer-aided manufacturing system 1500 include additive manufacturing system 1502 in communication with computer 1504 and coupled to build material source 1510. In some examples, computer-aided manufacturing system 1500 may include computer-aided manufacturing system 84 of fig. 20. For example, computer 1504 may be the same or substantially similar to computer 80. The build material source 1510 includes at least one source of polymeric material, such as at least one of the polymeric materials of the appliance body 102 described above. The dental appliance 1522 may be the same as or substantially similar to at least one of the removable dental appliances 100, 200, 300, 400, 500, 600, 700, or 800. In some examples, dental implement 1522 includes one of a set of dental implements 22.

Additive manufacturing system 1502 includes movable platform 1508 and extrusion head 1506. The movable platform 1508 and the extrusion head 1506 are configured to manufacture a dental implement 1522. For example, the computer 1504 controls the extrusion head 1506 and the movable platform 1508 to make a removable dental appliance 1522. Controlling extrusion head 1506 by computer 1504 may include controlling at least one of a material feed rate from build material source 1510 to extrusion head 1506, controlling a deposition rate of build material on dental implement 1522, controlling a temperature of extrusion head 1506, and controlling a position of extrusion head 1506. By controlling at least one of the material feed rate, the material deposition rate, the temperature of the extrusion head 1506, and the position of the extrusion head 1510, the computer 1504 can control the fabrication of the position, size, and shape of at least a portion of the dental appliance 1522. Controlling the movable platform 1508 by the computer 1504 may include: at least one of controlling translation of the movable platform in a plane perpendicular to a material deposition direction from the extrusion head 1506, and controlling elevation of the movable platform along an axis substantially parallel to the material deposition direction from the extrusion head 1506. By controlling at least one of translation and elevation of the movable platform 1508, the computer 1504 can control the manufacture of the position, size, and shape of at least a portion of the dental appliance 1522.

Although fig. 12 shows computer-aided manufacturing system 1500 configured for Fused Deposition Modeling (FDM), computer-aided manufacturing system 1500 may also be configured for Stereolithography (SLA), inverse photopolymerization additive manufacturing, inkjet/polymer jet additive manufacturing, or other additive manufacturing methods. In examples where the computer-aided manufacturing system 1500 is configured for polymer jet printing, the computer-aided manufacturing system 1500 may be configured to print multiple materials in a single print, allowing high modulus materials to be used for rigid components (e.g., shells) of the dental appliance 1522 and low modulus or elastomeric materials to be used for less rigid components (e.g., bendable tabs and/or arcuate members) of the dental appliance 1522. Further, with polymer jet additive manufacturing, the modulus may be selectively varied across the dental appliance 1522, and a modulus different from that used for the shell, for different portions of the flexible flap and/or the arcuate member, or for different portions of the shell, for example, may be used for the flexible flap and/or the arcuate member. Similarly, a different modulus than the shell used to reposition the individual's teeth may be used to anchor the shell.

Additionally or alternatively, manufacturing the dental appliance may include thermoforming and cutting material using a femtosecond laser controlled by a multi-axis robotic or CNC machine, such as to form slots, hinges, and spring features. In some cases, the depth of cut may be controlled to selectively ablate material in certain areas and reduce the thickness of the implement, such as to form a more flexible hinge axis or to increase the flexibility of the spring element.

Additionally or alternatively, manufacturing the dental appliance may include forming at least a portion of the appliance (if not the entire appliance) by milling or otherwise machining the appliance from a solid block of material.

Additionally or alternatively, manufacturing the dental appliance may include thermoforming the appliance body (especially where different thicknesses or stiffeners are required), and dispensing the hot thermoplastic material onto appliances having other uniform thicknesses via heated extrusion nozzles using a multi-axis robot. This can be used to create a structure of greater thickness in the region. In a similar manner, the photocurable resin may be dispensed onto a surface and photocured, either immediately after dispensing, or after all features have been placed.

Additionally or alternatively, manufacturing the dental appliance may include pre-manufacturing of the bendable tabs and/or the arc-shaped members. The prefabricated bendable tabs and/or arcuate members may comprise a material such as stainless steel, titanium or nickel titanium (NiTi) and are bonded or fastened to an appliance body formed by other means such as by thermoforming or 3D printing. The advantage of this approach is that it allows smaller structures with greater force delivery. In such cases, the computing device will be used to select from a set of discrete pre-fabricated fins that meet the force and deflection criteria required to achieve the specified movement, and place to determine the optimal location to place on each tooth.

Fig. 13 is a flowchart illustrating a process 1600 performed at manufacturing facility 20 for constructing a set of removable dental appliances 22. In some examples, the set of removable dental appliances 22 may include at least one of removable dental appliances 100, 200, 300, 400, 500, 600, 700, or 800. Computer 80 at manufacturing facility 20 receives digital dental anatomy data 16 from clinic 14, including an initial position of one or more teeth of a patient and prescription data 18 (1602). Alternatively, computer 80 may retrieve information from a database located within computer 80 or otherwise accessible to the computer. A trained user associated with computer 80 may interact with a computerized modeling environment running on computer 80 to plan a treatment with respect to a digital representation of a patient's dental structure and generate prescription data 18 (if clinic 14 has not performed such an operation). In other examples, computer 80 may formulate a treatment plan based solely on the patient's dental structure and predefined design constraints.

Once the computer 80 receives the patient's dental structure, the computer 80 determines the size and shape of the removable dental appliance for the patient (1604). The removable dental appliance is sized and shaped to reposition one or more teeth of the patient from an initial position to a desired position when the removable dental appliance is worn by the patient. In the same or additional examples, computer 80 determines the size and shape of a set of removable dental appliances 22 for a patient that are configured to be worn in sequence.

In some examples, determining the size and shape of the removable dental appliance includes selecting the size and shape of the removable dental appliance with the computer 80 according to a set of predefined design constraints. The set of predefined design constraints may include one or more factors including, but not limited to: at least one of a minimum localized force and a maximum localized force applied to one or more of the enclosed teeth, at least one of a minimum rotational force and a maximum rotational force applied to one or more of the enclosed teeth, at least one of a minimum translational force and a maximum translational force applied to one or more of the enclosed teeth, at least one of a minimum total force and a maximum total force applied to one or more of the enclosed teeth, and at least one of a minimum stress or strain and a maximum stress or strain applied to the removable dental appliance when the removable dental appliance is worn by the patient and the enclosed teeth are in their initial positions.

During the determination of the size and shape of the removable dental appliance, computer 80 may analyze the forces on the patient's teeth and the removable dental appliance using Finite Element Analysis (FEA) techniques. For example, computer 80 may apply FEA to a stereoscopic model of a patient's teeth as the modeled teeth move from their initial positions to their final positions representing a treatment that includes an ordered set of removable dental appliances. Computer 80 may use FEA to select an appropriate removable dental appliance to apply a desired force on the tooth. In addition, the computer 80 may use a virtual articulator to determine points of contact between the teeth throughout movement of the modeled teeth during treatment. The computer 80 may also include bite contact forces such as interproximal forces in the FEA force analysis, which are combined with forces from the removable dental appliances during the design of the dental appliances in an ordered set of removable dental appliances. The computer 80 may also determine the order of tooth movement to optimize the application of force, reduce treatment time, improve patient comfort, etc.

In some examples, determining the size and shape of a removable dental appliance (e.g., removable dental appliance 100, 200, 300, 400, 500, 600, 700, or 800) includes selecting, with computer 80, a thickness of the appliance body (e.g., appliance body 102, 202, 302, 402, 502, 602, 702, and 802), at least one of the plurality of shells (e.g., shells 104, 204, 304, 404, 504, 604, 704, or 804), a bendable tab (e.g., bendable tab 108C, 208, 308, 408, 508, 608, 708, or 808), at least one bridge (e.g., bridge 109C, 209, 309, 310, 409, 509, 609, 709, or 809), an optional stiffening structure, or the like, to provide rigidity suitable for repositioning one or more teeth of a patient from their initial position to a final position when the removable dental appliance is worn by the patient. In some examples, the selected thickness may be between about 0.10 millimeters and about 2.0 millimeters, such as between about 0.2 millimeters and about 1.0 millimeters, or between about 0.3 millimeters and about 0.75 millimeters. In some examples, computer 80 may also select a material for the removable dental appliance according to predefined design constraints.

The size and shape of the removable dental appliance of the patient may be presented to the user via the user interface 82 of the computer 80 (1606). In examples where the size and shape of the removable dental appliance is presented to the user via the user interface 82, the user may have an opportunity to adjust the design constraints or directly adjust the size and shape of the removable dental appliance before sending the design data to the computer-aided manufacturing system 84. In some examples, the size and shape of the removable dental appliance may be presented directly to the user by computer 80 when the removable dental appliance is manufactured by computer-aided manufacturing system 84. For example, computer 80 may send the digital model of the removable dental appliance to computer-aided manufacturing system 84, and computer-aided manufacturing system 84 manufactures the removable dental appliance from the digital model from computer 80.

However, even in examples where the size and shape of the removable dental appliance for the patient is presented to the user via the user interface 82 of the computer 80, after approval by the user, the computer 80 sends the digital model of the removable dental appliance to the computer-aided manufacturing system 84 (1608), and the computer-aided manufacturing system 84 manufactures the removable dental appliance from the digital model from the computer 80 (1610).

In some examples, computer-aided manufacturing system 84 may include a 3D printer. Forming the appliance body (e.g., appliance body 102, 202, 302, 402, 502, 602, 702, 802, 902, 1002, and 1102) may include printing a surface of at least one of the plurality of shells (e.g., shell 104, 204, 304, 404, 504, 604, 704, or 804), the flexible flap (e.g., flexible flap 108C, 208, 308, 408, 508, 608, 708, or 808), at least one bridge (e.g., bridge 109C, 209, 309, 310, 409, 509, 609, 709, or 809), an optional stiffening structure, and the like with a 3D printer. In other examples, forming the appliance body may include printing a representation of the patient's teeth (e.g., teeth 103) with a 3D printer, thermoforming the appliance body over the representation of the patient's teeth, and trimming excess material (optionally automatically by CNC or robotic machinery such as an end mill or laser cutter) to form a plurality of shells, at least one bendable tab, at least one arcuate member, at least one stiffening structure, and the like. The representation of the patient's teeth may include raised surfaces to facilitate forming at least one of the plurality of shells, at least one flexible flap, at least one arcuate member, at least one stiffening structure, etc. in the thermoformed and trimmed appliance body.

The technique of fig. 13 may be used to design and manufacture each removable dental appliance in a set of ordered removable dental appliances 22. For example, each removable dental appliance in the ordered set of removable dental appliances 22 may be configured to incrementally reposition a patient's teeth. As such, the ordered set of removable dental appliances 22 may be configured to reposition the patient's teeth to a greater extent than any of the removable dental appliances within the set of removable dental appliances 22. Such an ordered set of removable dental appliances 22 may be specifically configured to incrementally reposition the one or more teeth of the patient from their initial positions to a desired position as the removable dental appliances of the ordered set of removable dental appliances 22 of the patient are sequentially worn by the patient.

In some examples, the techniques described with respect to fig. 13 may be embodied within a computer-readable storage medium, such as computer 50, computer 80, or both. The computer-readable storage medium may store computer-executable instructions that, when executed, configure the processor to perform the techniques described with respect to fig. 13.

After designing the set of removable dental appliances 22, manufacturing facility 20 manufactures the set of removable dental appliances 22 from digital dental anatomy data 16 and prescription data 18 (1610). The configuration of removable dental appliance 22 may include 3D printing, thermoforming, injection molding, lost wax casting, 5-axis milling, laser cutting, plastic and metal hybrid manufacturing techniques such as snap fit and over-molding, and other manufacturing techniques.

Fig. 14 is a flowchart 1700 showing successive iterations of a treatment using an ordered set of removable dental appliances. The ordered set of removable dental appliances is configured to reposition one or more teeth of a patient. In some examples, the ordered set of removable dental appliances may include at least one of removable dental appliances 100, 200, 300, 400, 500, 600, 700, or 800.

Treatment begins at a first treatment iteration (1702). At the beginning of a first treatment iteration, the patient's teeth are in their initial positions as represented by the stop state X (1704). For example, as described above with respect to fig. 18, the patient's teeth are scanned to facilitate designing the ordered set of removable dental appliances (1706). From the scan of the patient's teeth, a computer, such as computer 50, determines at least one of the removable dental appliances in the ordered set, such as two different shapes and sizes: first setting X _a 1708A and second setting X _b 1708B. An exemplary technique for creating a digital model of a patient's teeth is described in U.S. patent 8,738,165 to Cinader et al, which is incorporated herein by reference in its entirety. The computer may determine the first setting X by first adjusting a digital model of the patient's teeth to create a model of the desired position of the patient's teeth after treatment _a 1708A and second setting X _b 1708B. The computer may then create the shape and size of the removable dental appliances in the ordered set based on the time and force required to move the patient's teeth from the initial position to their desired position. For example, the computer model may adjust the thickness, position, shape, and size of at least one of the plurality of shells, at least one flexible flap, at least one stiffening structure, etc. of the removable dental appliances in the ordered set to produce the force required to move the patient's teeth from the initial position to the desired position. Modeling forces applied by removable dental appliances in the ordered set may also be moved based on incremental positions of the patient's teeth during treatment. In this way, the computer may design each removable dental appliance in the ordered set according to the expected forces exerted on the teeth in the predicted positions of the teeth when the removable dental appliance in the ordered set is worn by the patient during treatment.

In some examples, a first setting X may be used _a 1708A and second setting X _b Each of 1708B manufactures at least one (such as three) different removable dental appliances of the set of removable dental appliances to produce at least two (such as six) removable dental appliances of the set of removable dental appliances. For example, the first An arrangement X _a 1708A may be used to manufacture a first Removable Dental Appliance (RDA) X _{a, soft} 1710A, second RDA X _{a, medium} 1710B and third RDA X _{a, hard} 1710C; second setting X _b 1708B may be used to make a fourth RDA X _{b, soft} 1710D, fifth RDA X _{b, medium} 1710E and sixth RDA X _{b, hard} 1710F. The first, second, and third RDAs 1710A-1710C may have substantially the same shape and size, but may include materials with different stiffness characteristics. For example, the second and third RDAs 1710B and 1710C may have a higher stiffness characteristic than the first RDA 1710A, and the third RDA 1710C may have a higher stiffness characteristic than the second RDA 1710B. Similarly, the fourth, fifth, and sixth RDAs 1710D-1710F may have substantially the same shape and size, but include materials with different stiffness characteristics. In some examples, the first RDA 1710A may have the same stiffness characteristics as the fourth RDA 1710D, e.g., a relatively soft polymeric material. Similarly, the second RDA 1710B may have the same stiffness characteristics as the fifth RDA 1710E, such as a relatively higher stiffness polymeric material than the first RDA 1710A. Likewise, the third RDA 1710C may have the same stiffness characteristics as the sixth RDA 1710F, such as a relatively higher stiffness polymeric material than the second RDA 1710B.

The RDAs 1710A-1710F in the ordered set of removable dental appliances may be worn sequentially by the patient over time. For example, the wear time of each of RDAs 1710A-1710F in the ordered set of removable dental appliances may be between about 1 week to about 6 weeks, such as between about 2 weeks to about 4 weeks, or about 3 weeks. After treatment planning using removable RDAs 1710A-1710F, the patient's teeth may be at the final position of the first treatment iteration as represented by dentition state x+1 (1712).

Once the patient's teeth are at or near dentition state x+1, the patient may return to the clinician, who may evaluate the results of the first treatment iteration (1714). If the first treatment iteration yields an acceptable final position of the patient's teeth, the treatment may end (1716). However, if the first treatment iteration does not result in an acceptable final position of the patient's teeth, one or more additional treatment iterations may be performed. To begin the next treatment iteration, the clinician may perform another scan of the patient's teeth to facilitate designing a subsequent set of ordered removable dental appliances (1706). In some examples, the evaluation of the results of the first treatment iteration may include another scan of the patient's teeth, in which case starting the next treatment iteration may involve merely forwarding the digital model of the patient's teeth to the manufacturing facility so that another ordered set of removable dental appliances may be manufactured for the patient based on the new positions of the patient's teeth. In other examples, the newly acquired scan may be used to create one or more iterations of the removable dental appliance in the clinician's facility.

The technique of fig. 14 represents one specific example, and many modifications may be made to the technique of fig. 14 within the spirit of the present disclosure. For example, the ordered set of removable dental appliances may include more or less than six removable dental appliances. As another example, each removable dental appliance of the ordered set of removable dental appliances may have a unique shape and size, and each removable dental appliance of the ordered set of removable dental appliances may be made of a material having substantially the same or similar stiffness characteristics.

Various examples have been described. These examples, as well as others, are within the scope of the following claims.

Claims

1. A removable dental appliance, the removable dental appliance comprising:

an appliance body configured to at least partially enclose a plurality of teeth of a patient, the appliance body defining a housing configured to receive a tooth of the plurality of teeth in an initial position; and

a flap tethered to the appliance body by at least a bridge, wherein the flap defines a flap boundary region extending around a perimeter of the flap, and wherein the bridge extends between the body and the flap at or near the boundary region,

Wherein the tab and bridge are configured to apply a force to the tooth when the removable dental appliance is worn by a patient to cause the tooth to move toward a desired position and orientation,

wherein the bridge comprises at least one of: an arcuate spring bellows extending away from a plane of the housing; and a jumper including an elongated structure extending between a first end coupled to the body and a second end coupled to the tab.

2. The removable dental appliance of claim 1 wherein the tab is integrally formed with the appliance body to extend from a hinge, and wherein the tab is bendable about an axis defined by the hinge.

3. The removable dental appliance of claim 1 or 2, wherein the bridge is an arcuate spring bellows extending away from a plane of the housing.

4. The removable dental appliance of claim 1 or 2, wherein the thickness of the spring bellows is less than the thickness of the housing to achieve at least one of the following when the removable dental appliance is worn by a patient: concentrating strain in at least one spring bellows or reducing deformation of the housing.

5. The removable dental appliance of claim 1 or 2, wherein the thickness of the spring bellows varies along the tab border region.

6. The removable dental appliance of claim 3 wherein the spring bellows defines a shear force reduction region.

7. The removable dental appliance of claim 3, wherein the spring comprises a plurality of spring bellows, wherein each respective spring bellows of the plurality of spring bellows is disposed along a respective portion of the tab border region.

8. The removable dental appliance of claim 3, the spring bellows comprising at least one of arcuate, serrated, sinusoidal, pulsed waveform, or helical.

9. The removable dental appliance of any one of claims 1 to 2 wherein the tab is tethered to the appliance body only by the bridge.

10. The removable dental appliance of claim 3 wherein the spring bellows extends continuously along the entire boundary region.

11. The removable dental appliance of any one of claims 1 to 2, wherein the bridge comprises a jumper comprising an elongated structure extending between a first end coupled to the body and a second end coupled to the tab.

12. The removable dental appliance of claim 11, wherein the jumper has at least one of an arc, a zigzag, a sinusoidal, a spiral, or a helical shape extending between a first end of the jumper and a second end of the jumper.

13. The removable dental appliance of claim 11, wherein the patch cord defines a cross-section in a plane perpendicular to a longitudinal axis of the elongated structure of the patch cord, and wherein a shape, area, or aspect ratio of the cross-section varies along the longitudinal axis.

14. The removable dental appliance of claim 11 wherein the patch cord is under a bending or torsional stress when the removable dental appliance is worn by a patient.

15. The removable dental appliance of claim 11, wherein the patch cord is more flexible than the housing so as to at least one of reduce deformation of the housing or concentrate stress in the patch cord when the removable dental appliance is worn by a patient.

16. The removable dental appliance of claim 11, wherein the jumper comprises a plurality of jumpers, wherein each respective jumper of the plurality of jumpers comprises a respective elongated structure extending between a respective first end coupled to a respective location on the housing and a respective second end coupled to a respective location on the tab.

17. The removable dental appliance of any one of claims 1 to 2,

wherein the housing includes an inner surface defining a void within the housing and shaped to receive the tooth at the desired location, an

Wherein the tab and the bridge are configured to apply a force to a side of the tooth opposite the void to cause the tooth to move toward the void.

18. The removable dental appliance of claim 17 wherein the inner surface of the housing further defines a second portion of the void, wherein the removable dental appliance further comprises a second tab tethered to the appliance body, wherein the second tab defines a second boundary region at least partially surrounding a perimeter of the tab, wherein the second boundary region comprises a second bridge, and wherein the second tab and the second bridge are configured to apply a second force to a second side of the tooth opposite the second portion of the void to cause the tooth to move toward the second portion of the void.

19. The removable dental appliance of any one of claims 1 to 2,

Wherein the rest position of the tab projects inwardly into the space defined by the tooth at the desired position of the tooth, and

wherein when the removable dental appliance is worn by a patient, the tab is displaced to a deformed position to cause the force.

20. The removable dental appliance of any one of claims 1 to 2 wherein the tab comprises at least two discrete tab portions, the tab portions being movable independently of each other.

21. The removable dental appliance of any one of claims 1 to 2, wherein the appliance body comprises a single biocompatible polymeric material.

22. The removable dental appliance of any one of claims 1 to 2, wherein the tab defines a plurality of boundary regions defining a spiral configuration, wherein the tab comprises a plurality of tabs, wherein the plurality of bendable tabs define a plurality of boundary regions defining a spiral configuration.

23. A method of forming a removable dental appliance, the method comprising:

forming a model of a dental anatomy of a patient; and

forming a removable dental appliance based on the model, the removable dental appliance comprising the removable dental appliance of any one of claims 1 to 22.

24. A method of preparing a removable dental appliance, the method comprising:

receiving, by a computing device, a digital representation of a three-dimensional (3D) dental anatomy of a patient, the dental anatomy providing initial positions of a plurality of teeth of the patient;

determining by the computing device the size and shape of a removable dental appliance comprising a removable dental appliance according to any one of claims 1 to 22,

wherein the size and shape are configured to reposition one or more teeth of the patient from an initial position to a desired position when the removable dental appliance is worn by the patient, and wherein the size and shape comprise:

the position, size and shape of the housing;

the position, size and shape of the fins; and

the position, size and shape of the bridge; and

transmitting, by the computing device, a representation of the removable dental appliance to a computer-aided manufacturing system.